What’s the fate of your old computers when you get your new ones?

I am drooling over a new Vaio with 2 GB of memory that’s on a special in our local mall. My current Fujitsu is 2 years old, and works, but some applications such as PhotoShop CS2 have begun to get weary. The middle-class thrifty one in me feels guilty because my old machine is perfectly fine in reality. I could give it to my family but they either already have one or are happy with the old one they inherited from me (remember the days Thinkpads used to be amazing).

So my question: what do you guys do with your old machines that paves a guilt-free way for you to actually get your new PCs? Is two years a decent time to refresh my hardware?