Should you care about whether you can upgrade hardware?
An online discussion I was in today touched tangentially on the question of how important it was to be able to upgrade the hardware on non-server machines (and how upgradeable various sorts of them are). My view is more and more that it probably isn't all that important.
(To be clear, I'm talking about post-purchase expansion down the road, not being to add necessary stuff at purchase time. If the machine doesn't do what you need at the start, you just don't buy it.)
Historically, we've almost never expanded or upgraded machines. We buy them in the configuration we want, usually with some extra margin in things like RAM and CPU power, run them for BIGNUM years, and then replace them wholesale. By the time a hardware upgrade seems necessary and can be sold to the powers that be, you usually can't get the necessary hardware bits any more.
(And even if you can, the assumptions that you built the machine on may seem quaint and outdated, like 'SCSI drives are the way to go' or 'it's too early to trust SATA, we'll stay with IDE'.)
So, how often are real machines actually expanded or upgraded? My own suspicion is that most machines that actually get upgraded were underconfigured when they were bought, for whatever reason. (Price is one obvious one.)
(Thinking about it more, part of my lack of interest in upgrading machines is because I like to keep old machines in an operable state, either as backups or to be used for various undemanding things.)