A problem with using a large television as a computer monitor is that when viewing a standard size computer screen, say under 24", your eyes are moving around to see the various locations on the screen. If you start using 32" or larger screens, your eyes have reached the limit of movement, and you have to move your head to see what you want on the screen. This can start to cause some fatigue or dizziness when using the computer for a while.
I got a 32" 1080p TV for someone I do some work for, who has a tough time seeing, and he reported those problems. He also uses one of those kids keyboards with the big yellow keys. He still uses the built-in magnifier function in Windows 7, but I'll take a look at some of the suggestions in these comments for another option for him.