For a few reasons. Mainly because my job requires me to use a CAD program, and Intel's onboard video doesn't work--it just crashes because it's not really supported. (BTW-I bought a E420 to try a few days back and may have made some positive comments about it, but it ended up not working out, so I went with a W series Lenovo Thinkpad that was built for CAD and has a CAD-certified video card).
I switched jobs since buying the Dell 11z laptop, so it doesn't really fit my needs anymore. That, and I don't want a second lappy sitting around doing nothing.
And for the gaming system, I don't really play many games much anymore (and I have a PS3 too). Played portal 2 and beat it, and don't really have anything else I want to play. That and I'd like to build a do a completely new system since the Core 2 Duo desktop is about 3.5-4 years old now (the video card isn't, but everything else--memory, motherboard, CPU--is around that age). Basically, what I do on the desktop now can very well be done on my new laptop (actually, the new lappy is much faster than my desktop--being it's a mobile Core i7 versus a Core 2 Duo--plus the laptop has 8GB of RAM and I found that I can play some games on it--even though the video card isn't designed for games so it's not the fastest card.
I'm trying to simplify things a bit... I don't need extra laptops and desktops sitting around, only to be used a handful of times per month. I just figured I try to get something for them for now because the longer I wait, the less they will be worth as time goes on, I guess.
There is nothing wrong with either system... they're just not really being used much any more. I don't have time for game playing anymore, and that's the primary reason I had the desktop to begin with.