Its been a long time coming but I've finally got a little time for it.
Mutants and masterminds
Mutants and masterminds is in my opinion one of the best game systems out there. Primarily designed as a superhero game the system is incredibly versatile, allowing players to create virtually any power they can think of and maintain game balance. How do they maintain game balance with such incredible variety you ask, simple, everyone is a superhuman and therefore rediculousely powerful, thus making small differences in power level almost meaningless.
Speaking of power level the game has that as a built in limiting factor. A character cannot possess more ranks in a power than his/her power level thus stopping players from overdoing one aspect of their character and then bitching about it when a mildly intelligent opponent exploits one of their many weaknesses.
Mutants and masterminds is based very loosely on the d20 system (that's d&d folks) but only requires one actual d20 to run. Its got a few contreversial changes from regular gaming, such as the removal of hit points from the game. The character now has a save against damage (which is now a static value) instead of hit points and depending on how well or badly the victim of an attack rolls their save decides the result of an attack. this can actually add a level of realism to the game, with truely pathetic attacks rarely managing to so much as annoy a heavy hitter, while allowing a lucky (or unlucky save) shot to do some damage.
There is very little in the way of roleplay rules in the game however, no morality compas, no mechanics for social situations beyond a few skill checks. I consider this a boon and a hinderance depending on the player. On one hand role play runs little to no risk of becoming 'roll play' by being over burdened by rules and mechanics. Some players, however, do need a little push to get them actually role playing rather than playing a character sheet, and morality rules tend to help these players along.
All in all I enjoy Mutants and masterminds as a game system, but the more serious a game becomes the less appropriate this system seems to become. In my opinion it seems better suited to more light hearted or over the top games, rather than a hard RP sessions with little action and more interaction.