Most powerful combined suite of apps IMHO Debian(all versions), KDE!
Most useful apps daily Emelfm2, Becomeroot, Quiver, Skype(no video though )
Games I play often Barrage, AisleRiot.
The new Diablo update is pretty good, especially the speedier web.
Just don't understand why Nokia doesn't integrate the dual boot setup we have into Diablo updates. Overall now most apps work well with latest Diablo update.