Im surprised someone hasnt said it yet, but dell makes good monitors! (just not good computers, heh) I really like my 20" wide screen monitor from dell. It uses the same glass/screen as the 20" apple monitor. The only difference is the dell has better circuts with more options for inputs.
acer is good too. but cheap. which can be good or bad. i have one at work that has 5 dead pixles. not enough for a repair, but enough to be annoying! my brother has an acer and he has power supply problems. his just wont turn on sometimes, but its not consitent enough to get a repair through the warranty!