Forget about Nuendo right away, unless you are really into tv post or surround. Cubase does the same for much less money (the fact that many people have Nuendo here is most likely because they have a hacked version ...).
I had a trial version of Reaper and it wasn't too intuitive for me - and I never tried Sonar and Samplitude. If you are working with Midi a lot, I'd advocate Cubase (which is my DAW of choice). Oz and others have been really pushing Sonar, but it seems they are recording more than me ...