Why would anyone ever take one level of Wizard and all the rest Sorcerer? Same as one level Sorc and all the rest Wizard. D&D rewards focus. Getting higher-level spells faster is better than whatever the other class would have bought you.
Sorcerers have Kn(Arcana) and Spellcraft as class skills. How would a level of Wizard help?
Anyway. Sorcerer is a fine class. It starts slowly but is playable with the right Feats (specifically, Draconic Feats).
I'll show you how I'd build a Sorcerer, with an eye to utility & flexibility. Let's assume 25 point buy and just Core stuff plus Complete Arcane, so your actual build will probably be stronger:
Human Sorc
Str: 8, Dex: 13, Con 12, Int 14, Wis 10, Cha 15
1: Sorc 1 -- Draconic Heritage (Gold), Draconic Breath -- Silent Image, Charm Person
2: Sorc 2
3: Sorc 3 -- Draconic Flight -- Shield
4: Sorc 4 -- Cha +1 -- Glitterdust
5: Sorc 5 -- Mage Armor, Alter Self
6: Sorc 6 -- Draconic Power -- Haste
7: Sorc 7 -- Magic Missile, Hideous Laughter, Suggestion
8: Sorc 8 -- Cha +1 -- Black Tentacles
9: Fatespinner 1 -- Draconic Legacy (Bless, Daylight, Dispel Evil) -- False Life, Slow, Resilient Sphere
10: Fatespinner 2 -- Wall of Force
11: Fatespinner 3 -- Mirror Image, Magic Circle vs. Evil, Unluck, Sending
12: Fatespinner 4 -- Cha +1 -- Spell Focus (Enchantment) -- Planar Binding
13: Argent Savant 1
14: Argent Savant 2 -- Scrying, Teleport, Greater Dispelling
15: Argent Savant 3 -- Spell Focus (Conjuration) -- Limited Wish
16: Argent Savant 4 -- Cha +1 -- Break Enchantment, Analyze Dweomer, Plane Shift
17: Argent Savant 5 -- Polymorph Any Object
18: Mindbender 1 -- Skill Focus (Spellcraft) -- Greater Arcane Sight, Mind Blank
19: Archmage 1 -- Shapechange
20: Archmage 2 -- Cha +1 -- Greater Planar Binding, Wish
Toss in a level of Wayfarer Guide if you want to spend skill points on Kn(Geography) -- only Argent Savant gets that as a class skill, but it's a nifty PrC if you take only one level.
Keys to the build:
- Put 5 ranks in Prof(Gambler) immediately. It's a class skill for Sorcs, and you need it for Fatespinner.
- Take 4 ranks in each of Bluff (easy), Diplomacy, Sense Motive and Intimidate (all cross-class), before you can take Mindbender. Telepathy 100 ft. is well worth the skill points.
- You have no free Feats. You must take Spell Focus twice by the end, so maybe it would be better to choose more spells with saves.
- Now personally, I like the Gold Dragon Legacy spells. However, there are some more strictly combat oriented Legacy types. Blue, Green, Copper and Red are also excellent -- note that you do NOT have to be evil to take Blue, Green, or Red, nor do you need to be LG to take Gold. It's just a flavor thing.

- You have hardly any direct-damage spells. This is on purpose. Basically you're supposed to use your breath weapon or Magic Missile until you get Arcane Fire (via Archmage). The rest of the time you buff the party, or take opponents out of the fight using effects like Suggestion, Resilient Sphere, Wall of Force, etc.
- Likewise, no Fly spell. At early levels, you can get around this with Draconic Flight. Later, use Polymorph, Poly Any Object and Shapechange.
- You have a large variety of special abilities. Be sure you know them. You're very flexible -- the opposite of a one-trick pony.
-- N