You (I mean I) can see the difference from a meter and even more..
I'm using 22" ISP LG TV/Monitor from a ~100cm (from time to time) and the pixels are more then obvious (especially when you reading)!
I'm retina user from a ~month and I still smile each time I sit in front of my retina 13" MBPIt's just AWESOME.
Is that display 1366x768? Most small TVs like that are only 720p.
I have a cheap Acer 21.5" 1920x1080 screen attached to my MBP (so same pixel density as current iMac, just a crappier panel) and at 2 feet (~60cm) I can't resolve the pixels. I have 20/15 vision.