Looking over my 3.0 MM:
A vampire has certain natural advantages that many class abilities simply remove. Energy drain only applies to their slam attack, so you can't flurry-of-blows an archmage into negative levels. A monk who gets vamped can no longer gain monk levels, because of alignment changing to chaotic.
I think the best choice for a close combat type would be a barbarian, because of their rage ability. It'll pump up their strength, thus their slam attack does more damage and is likelier to hit and drain. It'll also make grappling people easier, so you can suck zeir blood, ma a ha.
Fighters and monks will benefit from the heightened vampiric physical stats, but not as much as a barbarian, I'll wager. A temporary strength of 30 or more is nothing to sneeze at.
A sorcerer is a completely different proposition. Their Charisma isn't bumped as high as Strength, but on the other hand, all vampires are pretty lethal in combat, so the paltry +4 Cha gain will merely make him a lethal spellcaster with equally lethal melee abilities.
I've used vampire wizards (called sorcerers because it sounds cooler) in my webcomic, link in sig. It's down right now, though.