Man in the Funny Hat
Hero
It's a tough call for me. My initial response (and therefore the one I'll stick with) is Star Wars d6. When I ran it I was the biggest SW geek. (Episodes I-III killed that.) It took a lot of energy to keep up the pace but it was a BLAST.
Traveller is a VERY close runner up. I played a LOT more Traveller than I ever ran SW, but the GM's were always combining it with Space Opera, later Traveller flavors and so forth, and I never owned any of the rules while we played which means I never quite grokked the system.
An equal runner up would be Marvel Super Heroes. I don't know what it was about MSH but I thought it was fantastic. Again the downside was that I never quite grokked the rules because at the time I was playing I didn't have proper access to the rulebook.
None of them ever threatened D&D as my favorite.
Traveller is a VERY close runner up. I played a LOT more Traveller than I ever ran SW, but the GM's were always combining it with Space Opera, later Traveller flavors and so forth, and I never owned any of the rules while we played which means I never quite grokked the system.
An equal runner up would be Marvel Super Heroes. I don't know what it was about MSH but I thought it was fantastic. Again the downside was that I never quite grokked the rules because at the time I was playing I didn't have proper access to the rulebook.
None of them ever threatened D&D as my favorite.