My all time favorite game and game system is the long out of print Top Secret/S.I.
from TSR. I think it is one of the smoothest percentile based systems I've seen and I think it deserves a retro-clone treatment, like OSRIC or Four Colors (4C) (stripping the system out of the setting and using it as a generic gaming system for most types of games). The biggest mark against TS/S.I. is that the fan base is almost non-existent. There are many out there who love the game, but the number of people who still play and support it is shrinking. That holds a lot of weight for me.
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The last system is True20
. This one was a pretty good attempt to take 3rd edition Dungeons & Dragons (d20) and strip away a lot of the battle mat tactics out and have a near compatible d20 system. True20 is far easier than D&D and probably moves along much faster, as well. The fan base for True20 is out there, though I don't think it is as big as Savage Worlds. I even tried my had at contributing by starting the unofficial True20 Wiki page.
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