I sold realflight G4 after upgrading to G4.5 and having too much greif from knifeedge over it (long story).
The only sim I really use anymore is FMS which is a free RC flight simulator. No fancy graphics or fancy flying but I don't need that anyway.
I also have Reflex XTR wich I got for $10 but I rarely use it although it is a good sim.
If I do buy a sim again it will probably be Aerofly 5 or AFPD. I have used a friend's and I think it is better than Realflight. Better support too.

I wish I spent the sim money on planes though.