I firmly believe the future lies with DAWs like Reaper and Studio One. The former is all about customer interaction/satisfaction and constant update roll-out, while the latter is all about work flow, usability, and catering to the lowest common denominator functionally.
Cubase and ProTools are too stagnant and will eventually fall behind in the game. On the Avid side, PTLE and HD are not great options to buy into at the moment. On the Steinberg end, they have shown that they have no interest in listening to their customer base, and consequently users are moving in droves over to Studio One, which is a more streamlined version of the Nuendo concept. It's not fully-fledged yet, but when it is it will likely become a top contender.
However, as it stands, Cubase 5 is presently the best developed, affordable, fully functional DAW suite for a PC user. I've tried to get away many many many many times, but I always come back. Nothing else is quite as functional, reliable and affordable for what you get. I'm sure Reaper and Studio One will catch up - it's only a matter of time, but for now Cubase is still on top.