Anyone uses 2 monitors hooked up to one CPU?

I have this custom-built system for over 5 years now. It has a dual-head Matrox graphic card to support 2 monitors.

I need a new computer because:
1) the hard drive is about to die.
2) the motherboard has had annoying issues and it is time to get a new CPU.

My problem is: most ready-made computers on the market now all have graphic chip built in on Motherboard. So I cannot just swap out the stand-alone graphic card with a dual-head graphic card.

I discover Matrox now has a software solution to support dual monitors. It is called DualHead2Go and TripleHead2Go.

http://www.matrox.com/graphics/en/gxm/products/dh2go/home.php

The software solution is portable - it is an external box that one can hook it up with any computer.

Anyone here who use multiple monitors? What would be your recommendations?