Any question answered...

since people are talking clip systems... which are considered to be the most FG/SS friendly?

whilst I like my Crank Brothers egg beaters, I know that they are no good for FG, and I suspect that they may be involoved in my shoes snapping.

Pondering going down the road/3 hole systems, how much better than 2 hole systems (eggbeater/spd's/etc) are they?

The stiffnes and fit of your shoes is ten times more important. The added mount area of 3 hole systems gives a slight advantge. But its not massive.

My fixed gear has Crank bros quattros, and I have some 3 hole mounted cleats for them. So best of both worlds. Plus I can use any of my crank bros cleat fitted shoes with the bike.

Its been covered on other threads. But a MTB pedal, with a patform, gves the best compromise, of performance, and convenience IMHO.