http://www.9xmedia.com/ has an unbelievable array of choices for multi-monitor setups. I have three samsung monitors and have used them for years. Excellent monitors.
My brother is also a programmer and has eight monitors which is a bit out of control. I have four and find that 3-4 is the sweet spot for me. I have them arranged in a line and if I'm on a far left or right monitor, I'm not watching the other end. Most of the that's not a problem. I think 2-3 is what most people should be using. My brother found a Microsoft study that found a second monitor increases efficiency by 40-60%. I completely agree. I know one trader with a 40"+ plasma screen mounted on his wall...