having played a lot of games over the years I have come to the conclusion that what is important to a system in order is: character creation, combat, and skill resolution.

Character creation is the big one.  I want my character to be different from others.  Playing WoW and having the same 1st level dwarf paladin as everyone else is lame, as is hitting level 80 and having essentially the same one as everyone else because although there are choices in reality everyone chooses the same thing.  HERO is for me the ultimate character creation game.  I used to just make new characters for fun.  For this reason I prefer point based games over level based games.

Combat is the heart of most games.  Therefore I want it to be interesting.  Specifically I want options in combat.  Just attacking over and over again mindlessly gets old fast.  Combat does not have to be realistic.  It should be reasonably fast - I want my turn to be slow but everyone else's to be fast.  And I want combat to vary by setting and foe.  If fighting skeletons on the stairs in the dark is the same as fighting orcs in a grassy field at noon, I have a problem with that.  A problem with point based systems is that actions tend to be simple and similar.  D&D could create incredibly diverse spells because they simply made them up - in HERO the mechanics of creating them tend to make them really play the same.

Skill resolution is the least important.  I want it to be predictable and easy.  If my character is good at sneaking, he should be able to succeed most of the time.  I don't need a lot of rules around it - just a simple mechanic for it.  I have found that having a lot of skills was annoying because it meant that it was hard for a character to be good at what you think they should be good at. 

I am reasonably happy with Savage Worlds.  Characters are somewhat diverse, combat has its options (and you can create more edges to provide more options) and skill resolution is very simple.  What bugs me about it is the lack of attributes really affecting skills, and some specific actions.