i would love to give you an insight, i researched the market alot for a good 22inch, and here is what i found, go for either dell or acer, viewsonic is second priority, i'm an animator and brightness and color quality are key to me, i shortlisted two monitors dell sp2208wfp(15,400Rs) and acer al2216wbd(10,500):
Dell pros: Amazing sharpness, Great Gaming Monitor, Webcam, Hdmi Output
cons: Online order is a hassle, Too Bright, Colors are Saturated (compared to Acer), Pricey
Acer pros: Amazing Colors, Excellent for Graphics and Movies, Brightness that can be compared to apple cinema display, Great Value for Money.
cons: Response Time, Very Little Backlight Bleed.
since u have a hd4850 (i do too) i wud suggest go for acer and dont worry about response time (u can easily cure it by turning vsync to always on in hd4850) and ofcourse the huge price margin.
22" is sweet spot for surfing, gaming and movies, 24" is no-no for gaming, but for movies the bigger the better
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Hope this helps Bro