This topic got a lot more debate in another forum where I posted it, and here's the conclusions I came to:
In D&D 3.5e, vampires are "old school" bad guys who are basically indestructible save a few very specific weaknesses. If you're looking to mow them down a la "Blade," work with your DM to insure s/he's got a weaker version to throw at you.
Along similar lines, you can't stake a vampire through the heart during combat. The logic behind this is roughly akin to why you can't try to, say, cut someone's head off or otherwise make a "called shot" (as noted above). The combat system simply doesn't support this cleanly.
Due to the vampire's various abilities (blood suck when grappling, change to vapor at will, immune to paralysis and sleep), attempting to stake a vampire before it is reduced to zero HP (thus forcing it to flee in vapor form to its coffin) will end in frustration.
If you want to / must kill a vampire outside of its coffin (say, because you don't know where that is or you can't get to it), try sunlight or running water.
In any case, thanks for all of your input!