To use magic the gathering terms (Note: most people fall into portions of these categories):

Spike: Someone who wants to win at all costs, including originality, logic, and even bending the rules so far they snap. They can completely break games (see: Punpun) or just be that thing that saves the party when it desperately needs it because they are an efficient character (see: any extremely efficient and powerful gish; probably an artificer XD).

Favorite Books: All of them. But usually only about ~5 pages from each.

Johnny: Johnny wants to play on his own terms. That is, he see's DnD as the perfect chance for creative expression and will stick to his own guns even at the risk of sub-par power. He'll commonly be the one to try to optimize the underused classes and create odd character types you'll never see anywhere else. Why play a Cleric to heal and buff when you can be a Truenamer Incarnum-user with Stigmata and Strongheart Vest to offset the con damage?

Favorite Books: Tome of Magic, The Quinessential Soul Knife, A WotC article you never even heard of posted by Monte Cook on a forum back during 3.0 beta days

Timmy: He wants to be a good character using the biggest and most impressive things he can find. He doesn't necessarily want to win at all costs like the Spike or combine weaker elements into stronger ones like the Johnny. He's the guy who uses all his spells in a single Time Stop + Delayed Blast Fireball blast on the first encounter and, thanks to Ultimate Magus' ability to reduce 1st level spells into metamagic buffs, leaves nothing left over for the final boss. They pick the Great Axe over the Scythe since it uses bigger dice, without realizing the Scythe does more technical damage when you account for its critical hit multiplier.

Preferred Books: Player's Handbook, Monster Manual 1, The Complete Series

Vorthos: Cares nothing for power or mechanics so long as its flavorful. Theme trumps everything. He'd prefer playing a level 1 commoner to a level 10 druid if he could narrate his 14 page back story to everyone about why he chose to be a chicken farmer and why he'll avenge the loss of his village ransacked by bandits a week before he joined the rest of the party, using his father's sword he found hidden in the rafters of his house while he tried to escape the marauders.

Preferred Books: Weapons of Legacy, Draconomicon, his own book he's been writing about his character who le-...I'll tell ya later.

Melvin: Melvin prefers mechanics over gameplay. That is, he's content to sit by and read some fascinating new way to apply spell components in an intuitive fashion that blows all previous spell-component mechanics out of the water. He loves exploring new mechanics and constantly rating them. He's most likely to change his character (or beg to DM) to try out something new. Probably homebrews a lot and dreams of working for R&D.

Preferred Books: Changes every week based on 3rd party updates and forum revisions that make the systems *so* much better. Also: Pathfinder.