Before I launch into the rest of my post... yes. Humans rock for swordmages. That extra at-will makes the game so much more rich and exciting for me... even though I pick the same three every time. Swordburst (to cut up swarms something fierce, and possibly to beef up with stuff like Solid Sound or Enlarge Spell or Arcane Admixture come Paragon), Lightning Lure (for the highly-situational-but-awesome "Get over here!" moments), and Booming Blade/Greenflame Blade (for "Hey, it's marginally better than a melee basic"). The only thing I love better than a Human Swordmage is a Human Swordmage/Artificer! Hello, Magic Weapon.
Like Obryn, Swordmage is my current favorite class. I suggest you give them a try. If they're not for you, hey, they're not for you, but for my money, they're the best warrior-mages out there. They nail the flavor perfectly without lots of multiclassing backflips. In an effort to sway you to the side of the Swordmage, here are some awesome things I've done with a Swordmage:
-In a recent game, my character was being introduced to an already-established campaign. The DM decided to have my character and another new character rush to the rescue of the overwhelmed party. The party was ambushed by ghouls and a massive unholy dog thing called a Hound of Doresain. It was Large size, consistently did twenty or more damage on a hit at level 3, knocked you prone on a hit, and could attack you again as an immediate reaction to prevent you from standing up from prone. Basically, it was a scary bugger. And my Swordmage all but soloed it.
My character fought it at the edge of a cliff, telling his companion to go on without him and help the rest of the party (so as to not look like I'm blowing my own horn too much, my companion was renau1g, and he very helpfully used Stirring Shout on the beastie before moving on). My Swordmage used Lightning Lure to drag the hound away from the overwhelmed party, then marked it. When it naturally decided to attack me, I punished it with a Frost Backlash, and spent the rest of combat narrowly dodging its attacks and shaving off chunks of HP with Booming Blade. I took a beating, but I don't think it successfully attacked anyone else during the rest of the combat. I actually got to use the phrase, "Go on without me, I'll hold 'em off!" and it didn't bite me in the butt! Imagine that.
-In another campaign, I was teamed up with a Dragonborn polearm Fighter, among others. Some people like to call Swordmages "secondary defenders." While I see that as something of a slur against my favorite class, I do have to admit that it was a lot of fun playing with another defender, and we managed to force some monsters into some truly bad situations by strategically swapping marks.
Once, we encountered a spider of some type in a very narrow tunnel. The spider itself was tough, but alone, and we could've easily surrounded it and taken it out. But we believed there may have been trap ahead, so we decided to play it safe. With my amazing Swordmage AC, I body-blocked the thing, while the Dragonborn Fighter behind me poked at it with his halberd to keep it marked. With my naturally-high AC, plus the Fighter's mark, the thing had virtually no realistic chance of hitting me.
-In that same campaign, we fought a very scary elemental of ice and winter in a frozen-over wizard's tower. It divided us, knocking some of us straight off the tower, and the fight started off very shaky. But then my Swordmage used Transposing Lunge, teleporting the creature into a nearby room. The Large creature had to squeeze through the small doorway to get back at us, granting us combat advantage against it, in addition to other lovely perks and debuffs. Me and my Fighter buddy then re-attempted the Body-Block Special, but sadly it whipped out a massive close burst pushing power that knocked us all back. Still, it was a brilliant plan, and it bought us a precious round to regroup.
-One of my first ever Swordmages, an eladrin, was part of an online campaign. It was some DM's take on the Keep on the Shadowfell, but it was really weird and he took some real artistic liberties. There were lots of confusing NPCs and ham-fisted intrigue, some annoyingly unkillable brooding DMPC-guy, and I remember him handing out a +6 amulet to a level 1 character. Anyway, it was a crappy campaign, and I soon left it, but it started out with a bang.
My guy was an Assault Swordmage, and were fighting some weird humanoids made of blood and raven feathers (still no idea what the crap they were supposed to be). We charged into the fight like over-excited 1st level characters are supposed to, only to realize that these guys were actually really tough. I remember I attacked one guy, and ran him through with my sword. Apparently a minion. Then I marked a nearby guy, and Fey Stepped next to another, used an Action Point, and brought that guy down to bloody. Later, I used my immediate reaction to teleport next to and attack the guy I marked, and I ended up killing that guy, too. In basically a round and a half, I managed to kill/seriously mess up three of these feathers dudes, and I felt like a rockstar. The DM later admitted that the fight was way above our level, and he had honestly expected us to lose. I've been in love with Swordmages ever since.
Now, a word on Swordmage powers:
For At-Wills, I like Lightning Lure and Swordburst reasons I described above. You'll likely want at least one weapon attack, to make use of that higher damage die you get from a superior weapon should you choose one (and you likely should. Bastard swords seem to be the most popular). My favorite weapon attack is Booming Blade. It does as much damage as a melee basic, with the threat of doing more if the enemy moves away. It helps to alleviate some of the Swordmage's much-maligned "poor stickiness." Consider taking Solid Sound at Paragon Level along with Swordburst and Booming Blade to create a fun "force-field" Swordmage. Greenflame Blade is a solid option, provided you have high Strength. Some recommend taking it even with 12 Strength as a "minion-popper," but I frankly think Swordburst is the better choice if you're honestly worried about minions. Luring Strike is serviceable, if not eye-popping, but it's always good to re-arrange the battlefield, and we all know that the Swordmage is all about mobility. I'm unfamiliar with Frigid Blade, so I won't comment on it except to say that it could be quite good for a Swordmage with high Con, and seems to fit in with the Ensnaring Swordmage's overall "strategy."
From the verdant and fecund valley of the At-Wills, we descend into the barren, heat-wracked desert that is their Encounter powers. Make no mistake: I love Swordmages, but I hate their level 1 Encounters. Lightning Clash is outright terrible, Flame Cyclone is serviceable for Assault Swordmages but a rather yawn-worthy close blast attack for everybody else, and Sword of Sigils, while good, is frankly more complicated than it has any right to be. I have yet to come up with a favorite, because they all leave me cold. My advice is just to pick whatever looks cool to you, and to swap it out as soon as possible.
And then we get to the Dailies. For Assault Swordmages, the choice is clear: Burning Blade. Burning Blade, Burning Blade, Burning Blade. Burning Blade+Greenflame Blade frankly makes a Tiefling Assault Swordmage a tempting prospect, at least at level one. For everyone else, the fan favorite seems to be Frost Backlash. Unusually high damage for a Swordmage at 3[W], and it's used as an immediate reaction, meaning you attack 'out-of-turn'. It's a surprise, and lets you 'nova' for a while. And yet... I'm not a fan. Swordmages are Defenders, not Strikers, and they should be saving their immediate reactions for their Aegis. If you have decent Con, consider instead Dimensional Thunder or Lashing Asp. Frost Backlash isn't a bad choice, not by any means, but I don't think it's the must-have that many people make it out to be.
Finally we come to the Utilities. Here are some of my favorite Swordmage powers, among them Dimensional Warp. Dimensional Warp doesn't look like much on paper, but listen closely. Almost every story of thrilling Swordmage heroics you hear features it prominently. It lets you pluck an ally from danger and get all up in an enemy's grill at the same moment, all at the low, low cost of a minor action. In general, look to take as many teleporting powers as you reasonably can (Armanthor's Step is another gloriously shiny one). The standard Swordmage strategy is "mark and move on," and teleporting powers make that much easier. This goes double for Assault Swordmages, who need to "move on" a little more often.