I'm actually going to say something different....
Since it sounds like you're on a little bit of a limited budget here, this might not be viable for you. But I'd personally recommend one of the 24" LCD monitors, vs. two 19" displays. I actually upgraded my Mac Pro to a pair of 20" wide-screen panels, thinking "Wow! 40" of total screen space! This is going to be great!" Within 3 months, I took them back off the system and have them for sale now.
I found an Acer 24" LCD for sale locally for under $700 (or something like a Dell 2405, refurbished, off eBay would be a great option as well).
My problems with dual displays were:
1. For gaming, they're totally useless. Everything just happens on one monitor and the other stays blank.
2. The border between the screens distracts me when I'm trying to work with a program that's stretched between the 2 displays. I always end up sizing and positioning individual windows so none of them cross over between the displays, and that's really annoying.
3. You have 2 power cords to deal with instead of just 1 for your display. This can mean your surge strip or UPS backup doesn't have enough free outlets anymore. Plus, it's one more device to turn on and off, if you like to power your system off when it's not being used for a while.
With a good 24" panel, you have quite a bit of screen space, and it's all usable by *all* your software, 3D games included.
I need to replace my LCD monitor and have done some research on a replacement. I was all set to go the 22" Samsung 226BW for about $300 from Compusa. However, I have heard a lot of positive things about having dual monitors (yes, my video card has two dvi outputs). I do home video editing and general computer stuff... Looking at going two 19" monitors for around 200 each, so about 100 more for the dual set up... Is there a real benefit? Thanks!