since i am neither an np or a crna, my advice may not mean anything to you. since i work with both, perhaps it will.
if you've worked in the or for six years, you have a far better idea than most nurses who start anesthesia school what exactly a crna does. if it isn't calling to you, it probably isn't for you. graduate school is expensive in time, money, work and sacrifice. if crna isn't something that you really, really want, maybe it's not worth it.
icu experience is valuable whether you ultimately decide to go to anesthesia school or decide you want to go the np route. any icu -- ccu, micu, sicu, etc. -- will give you experience, but if there's an option go for a cardiac sicu. you get much more hands on experience with central lines, swan/ganz catheters, balloon pumps, cardiac devices, arterial lines, etc.
but here's another thought that isn't on your list: once you leave the or and start caring for awake patients at the bedside, you may find that you love that and don't want to leave. and that's ok, too. we need bedside nurses, especially good ones.