We've used a lot of the systems on the list (and some that aren't), so I'll just limit myself to what we're using right now.
Currently, we're playing a Trinity game converted to GURPS 4e (and with the added weirdness of using the old Masterdeck cards, too). It's very cool.
We're also filling in with an Arcanum game using the new World of Darkness ruleset. You know, the nerdy nonviolent hunters group from the old WoD.
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and i hope that someday soon we'll get to go back to farscape d20 and our murpg game
ryan