um, i don't really know what true blood is and i know about twilight a little. they constantly make these because all the adolescent love those kind of vampire/love thing stories, i guess. well from what i've read here and on google True Blood sure sounds like the better one out of the two, i will pick that one.
for you guys that like that kind of stuff you should probably take a look at Interview with the Vampire with Brad Pitt and Tom Cruise, i genuinely enjoyed that one.
and for people that like more classic vampires you should take a look at Tom Browning's Dracula, because it's a true vampire, not silly vampire kids and stuff.