Probably the most common type I see in fiction that D&D cannot do is the guy who is equally as good with a blade as he is with magic.
No, the only type that D&D cannot do is a guy
who is equally as superior to other characters with a blade as he is superior to them with magic. D&D has alot of ways to do a character who can both wield a blade and wield spells.
In 1st edition you could do it directly, as a fighter/M-U. In 3e edition, you can get there through a slew of classes and prestige classes. Heck, strictly speaking you could just divide your classes among fighter and wizard. But inevitably, these things don't seem to satisfy the person who wants to play "equally as good with a blade as he is with magic" because thats not what they really mean or desire. What they desire is some who is both superior with the blade and superior with magic. But this desire is at odds with the fundamental rule of role-playing, "You can't be good at everything." (Or as one of my players put it, "Nothing is free.")
It's a pretty difficult design problem, and there are only a few ways off the top of my head that I can see a system overcoming it. You could make magic much less powerful and versital than it is in D&D and if you do that you'll run into people complaining that they can't play the mighty wizards they encounter in fiction. Or you could make everyone mighty wizards by default, and make 'swinging a sword' one of many secondary skills that they could take, but this will also lead to complaints about the ability of the system to generalize (what if you don't want to play a mighty wizard?). Or you could use a generic system so that there wasn't anything that casting spells could do that swinging a sword couldn't do, and vica versa, and the only difference between the two was how you fluffed the crunch.
But as far as simply being good at both magic and swinging a blade, if you were to play a solo adventurer who was a ftr6/wiz6 in a sandboxish campaign, you'd be percieved by people as someone who was both good at magic and a master swordsman. The problem is the player wouldn't be comparing himself to the NPC's or the particular challenges he was being faced with, but to hypothetical 12th level fighters or 12th level wizards. However, this is not that difficult of a problem. There are a variaty of ways to build said character in 3e so that its closer in power to its 'peers' by effective level even without bringing up how you could house rule it.