I'd spend 850 -950 then you can get yourself something like an hd33 which is award winning full 3dhd. Its kinda like your telly but potentially 9+ times bigger. The ghosting is very low if any with dlp shutter glasses. Now obviously it won't be as good as your tv on a very bright day but close the curtains a bit ........simples squark.
720p is good too but for that bit more you are getting the best and will notice the difference.
However if 3dtv and gaming is your thing that's only broadcast in 720p and consoles 720p so 720p projector is fine.
If interested in 3d blu ray then well worth the extra step and too me is better than a lot cinemas as it's not polarised just a clean non ghosty image and you can fidly with the settings and focus.
Hd33 is about 1400 but you can find deals. If struggling let me know as I have one spare. I've got an optoma hd65, dell hd410hd and dell 4320 all 720p 3d all great with 3dxl(easier with ps3 or designated 3d blu ray than a pc).
Was happy with them but I like my hd33 too much now. I'm gonna get rid of them even had a 2 1080ps in a passive system with 2 3dxl's but not quite as good as one full 3d hd projector.
However whatever happens once you go projector tv looks pants.
If you go hunting on the bay for deals dont get one of these no name brands. Benq , optoma and dell are pretty good.
Also make sure you know how many hrs have been used and are left, although you can pick up bulb for about 70 these days.
I'm looking at over a 130 inch screen at them moment and projector less than 3m away.