Dungeons & Dragons - the game that started it all - 2nd Edition or older preferred; 3rd edition is a bit cumbersome, 4th sounds horrible.
Shadowrun - A messed up future where evil mega-corps pretty much run everything and where magic and meta-humans have “returned” and some of them are cybered to the max. Tends to be a fast paced kick in the pants. Catalyst Game Labs has an awesome Demo Team that runs “Shadowrun Missions” at conventions and game stores.
Here is my Optimal Use of Edge Chart. It shows you how to get the highest average Hits for your Edge. Here is my character tower to display basic character and player data for the other players and GM to see.
Serenity - One more way to continue experiencing the ‘Verse - RPG based on the Firefly TV series and Serenity Movie.
Top Secret SI - Modern spy game, your chance to be 007.
Cyberpunk 2020 - “High tech, low life roleplaying”. Pretty much Shadowrun without magic or non-human races.
Stargate SG-1 - based on the TV series
Castles & Crusades - similar to D&D.
Paranoia - a whacky sci-fi game in a world where a computer is the supreme leader, and things are really messed up. You won’t likely live long, but don’t worry the computer will send one of your clones along to carry on.