As an HTPC display? Probably. You might find that the Mini actually can't output the native resolution 1366 x 768 since it's not divisible by 8, and will instead default to either 1280x768 or 1360 x 768. Depending on the HDTV, either should look fine for video playback, etc.
As an actual desktop computer monitor that you'd actually want to do virtually anything with at close proximity? Bleh. HDTVs do not make very good computer monitors because the resolutions are actually tiny for the screen size compared to an actual computer monitor. And with resolutions less than 1080p, overscan can also be a big problem. (IE: parts of the OSX screen may sit outside the viewable area, like the menubar.)
Personally, if I wanted a 26" computer monitor and was basing it on price, rather than resort to a no-name HDTV I'd find a 26" computer monitor with a fairly decent resolution (IE: 1920x1200) in just a slightly higher price range.