I used to worry about that whole which socket is going to be around for how long, but over the last 5-6 years, I've realized that the processor and motherboard both become obsolete so fast, that I never get around to upgrading one or the other before I really want to upgrade both together. (Don't even get me started on "What kind of memory should I get? PC-3200, PC-4000 PC-99-99-99?") I just hand the old machine down or find something else to do with it. I do tend to reuse cases, power supplies, speakers, monitors, and to a lessor extent, video cards (and that's probably ending with PCI-express coming on) and audio cards.