I usually am the DM, DMed one group for 4 times a week, 5 years, got there characters to deep epic.
Anyhow, if I play, I normally play a Mage, as I like the resource management that 3.5 Edition requires. I've played a Male Human Necromancer, with a Spectral Loremaster class from a 3rd party source book, and a Female Grey Elf Loremaster. I have also played a Male Human Paladin, with a very low int, a religious zealot of St. Cuthbert. Really cool character as he was in almost every sense my polar opposite. Currently playing Female Human Cleric of Heironeus, with the aim for a gish build (fighter/cleric). It's a 2-people group, and the other person really wanted to play a spellsword-like character, so I decided to be the Cleric.
Stuff I would like to play is a swashbuckler-like fighter, you know, fast, flashy, backstabby with nasty sharp swords.
Stuff I likely will never play is a straight-out fighter or barbarian, a sorceror (the simple resource management isn't for me, strongly prefer the mage), or a monk.
In general, I do considerable powerplaying, but not to the absurd munchkin-extreme. Let's call it "efficient". Oh, and those who claim a paladin is weak: the exceptional saves, especially in a high-magic campaign, combined with a lance and ride-by attack, and good use of the smite are pretty strong.
<disengage extreme geek mode>