You sure can.
I used Aster for a long time at home to play games with my brother. I have an i7 920 stock and 18GB RAM with two GTX 260's and usually maxed out the 260's in any game first. You don't actually need separate video cards but it's less finicky and much faster, since they don't have to share VRAM. SoftXpand works for gaming too, but I haven't used it as much. It's not quite as simple to configure, even though it's a much more elegant interface.
Now to SoftXpand... I set one up for a customer with a paid SoftXpand. It's some lower end 3rd gen i5, 4GB RAM, a Radeon 6450 (just to have more ports) and a regular mechanical drive. They have three seperate users, and one has two screens to run a projector, a 70" TV, and a monitor. The projector and TV are mirrored, and running off of the 6450. Oh, and of course I use three keyboards and mice combos. Lots of USB. It runs surprisingly well. Of course it's slow to boot, and seems to be even slower at shutting down, but it does work well for them. They're really happy with it. But anything's an upgrade to a Pentium Dual core Vista laptop. One special thing is that the motherboard (Dell) allowed me to turn on the onboard video along with the dedicated card. Therefore I had lots of ports. IIRC to have multiple monitors on one user it needs to have it's own card. Maybe I'm wrong though. And of course, these people don't play games. Just docs, YouTube, web, PowerPoint.
Read the second sentence. Know it's for 3 users, and it worked well.