Ideal Size and Resolution HDTV for typical avi/mkv rips?

[Danteism]

Hoping some of the videophiles can help me understand what I should be looking for as I wade into my first flat screen TV purchase.

For years now I've watched 100% of my Movies and TV content on my 21.5" computer. I'm about to upgrade to a streaming set up and my needs are pretty humble. Basically looking for a 40-50" flat screen to use strictly for content streamed from my computer via roku or hacked apple tv. 99% of what I watch is downloaded tv shows (avi and mkv files) usually 720 max, with a very rare 1080 rip.

With files that are usually in the 1280x760 resolution range and sometimes only 624x352 I'm guessing it's best not to go too big and that more than a 720 HDTV is something I won't be getting the benefit of anyway? (or do the TVs upsample to a higher res and actually make a notable difference?)

Will be moving shortly so I don't know what the exact viewing room will be like, but being that it is going to be a small NYC apartment it's a safe bet that viewing distance is going to be somewhere in the 7-9' range. Not necessarily expecting exact model recommendations, but for what it's worth my goal is something in the $500 range with $650 being the absolute max.

Thanks in advance for your tips, insights, and recommendations.

[jagabo]

Start here:

http://hd.engadget.com/2006/12/09/1080p-charted-viewing-distance-to-screen-size/
http://www.thx.com/consumer/home-entertainment/home-theater/hdtv-set-up/

I have a 46" 1080p HDTV and can bear to watch 624x352 material from ~9 feet away, 1920x1080 material is optimal from 5 or 6 feet.

[Danteism]

Thanks so much for the links and personal experience. I'm thinking it might be best to stick with 42" then as I'm likely to be around 7 ft, and get mightily annoyed if there are very obvious artifacts and and blockiness.

[jagabo]

Many TVs and players have a "zoom out" feature. If you get one with that you can always just shrink the picture down until you can't see the problems. Then you don't have to worry about getting too large a TV.