Quote from LeeD:
More monitor space is better... So, widescreeen is a good choice as long as the price is agreeable.
A few things to watch out for:
1) Monitors whose size is larger than what the resolution warrants. You normally expect that 1600x1200 will be 20-21 inch, 1920x1080 will be 22 inch and 1920x1200 will be 23 inch. Any larger screen at those resoluytions just wastes desk space
2) Be very careful if you consider monitors with resolution higher than 1920x1200. Not only these command a massive price premium but it's such a small market that many leading brands haven't updated their lines for 3-4 years while the techonology has evolved a lot.
3) It's easier to arrange 4 monitors of the same size and resolution (it doesn't matter if they are different make)
4) If the monitor stand can't hold monitors you want the question is moot