At the moment I'm in a roto 12 team, 10 player keeper league which has now been in existance for about 5 years now.
Currently our stats are:
Runs, Singles, Doubles, Triples, HRs, RBIs, BA, OPS, SB
Wins, Holds, Saves. Ks, Taken Bases, ERA, WHIP, K/BB, CG
As far as those stats in particular...they work well, at one point we had Field % or Errors worked in...that was disliked, thus it was removed.
We also just made an innings cap this past season to prevent people from padding retroactive stats (mostly Ws and Ks). I'm still mixed on this being necessary as we have things like Taken Bases, ERA, WHIP, K/BB that should prevent owners from making weird starts for the sake of Ks and Ws.
Reasoning for 10 Keepers: Allows owners to build for the future long after they've been eliminated from contention. This of course has been countered by those looking to lower keepers with the theory that it allows owners to create powerhouse squads. Personally, I think if you want to win...you can win - new guys break out every year...
Minors: We're currently looking into starting one up, at this rate not this season.
Things to be careful about; Make sure you have solid owners in place...or at least keep an eye on owners not pulling weight. I can say that it really sucks when you finally get rid of a dead owner after 2 years only to see that the poor smuck taking over has to cope with an old injury riddled squad of has beens.
I think that's about it.