Yeah the best advice, if you think you'd enjoy a fantasy setting, is to pick up a copy of the Players Handbook for D&D and give it a whirl. Though they are both RPG's I'd have to agree that they are very different games. Thanks to the versatility of a DM (or GM) led game, though, you've got a lot of freedom as to how you aproach things. It's possible to have a combat fest in Vampire just as it's possible to sit around talking for a whole session in D&D.
At the end of the day, D&D is a great game, the mother of all RPG's and I'd recommend anyone interested in roleplaying to check it out, particularly if you enjoyed the computer games.
Thats my sales pitch anyway.
Have fun!