i have the A95f... i can never go back to a conventional curved crt. they looked too warped after using a flat crt.
at the same time, i don't see myself getting a flat panel until they have perfect response time (<5ms, at least), higher resolutions, and come down in price. maybe about 3-4 years.
i wouldn't go lower than 19", myself. but i'd only go 21" if i had room to scoot it back about 6 inches.
i hate sony's. viewsonic is decent. i've heard good things about samsung.