I got the 720 and upscale it when necessary and looks fine. As far as being obsolete, if you aren't working in film, they will probably be good for quite some time...heck it took 10 years for HD to catch on, you think people are about to rush out and buy 4K sets anytime soon.
All that being said, bigger is always better, so if you have the extra cash (& drives fast enough to handle all the extra pixels!!!!), you can't really go wrong going with the longer term solution.
Johnny Cuevas, Editor
"I have not failed 700 times. I have succeeded in proving that those 700 ways will not work. When I have eliminated the ways that will not work, I will find the way that will work."
---THOMAS EDISON on inventing the light bulb.