There are two factors (imo) that makes the TV display nicer pictures than your pc:
I notice that my TV (LG42LD520) does quite a bit of processing on the pictures when I use the USB port to view pictures; it usually ups the brightness, saturation, contrast, and sharpness. The sharpness boost in particular is remarkable, it seems like the TV is so smart it knows just how much to apply without it looking oversharpened. It actually does the same thing with digital signal as well, as watching Planet Earth with "standard" picture enhancement is light years away from "off." Supposedly a custom enhancement setting would be best, but I haven't played with it enough to see if it would make a difference.
Also, a lot of TVs these days are IPS panels. My TV is one, and it basically just means higher quality, and will look significantly better than most Computer LCDs (mine is a 22" Acer TN panel). Supposedly IPS computer monitors such as the Dell's U2311H or Apple's cinema display would come closer to the TV quality. Remember that the TV applies enhancements by default, so to achieve the same results you probably have to photoshop it to some degree on your monitor.
For the DVD issue, my guess is that your TV doesn't enhance the pictures when fed with signals from the DVD player. If you can set up your TV to enhance the pictures from your DVD player, then the results would be similar as putting memory card direct to the TV.
By the way, how is #1 and #5 different?
Last edited by Andi Lo; 04-04-2011 at 12:37 PM.