I currently have a 23" monitor, and I'll be ordering another one in a week or so. Even two 23" seems like more than enough. http://www.newegg.com/Product/Product.aspx?Item=N82E16824236059
I have a Samsung SyncMaster 2333SW which has a TN Panel and there is no problem with color shifting or poor viewing angles at all. But EarthQuake is right, getting one with a good panel(most TN panels are really shitty) should be your highest priority.