Well, I'm keeping an Apple II+ around because I know that it will be my only functional link to the past one day. Computers like the Amiga and Macintosh have too many custom chips or ephemeral parts. Most of the components are socketed, which makes servicing easier (desoldering n-pin components where n > 2 is tricky). I also have a guide or two that discusses what signals I should see from the various components, and what to do if the signal is different. Though I still have to learn how to use a book as sophisticated as that.
As long as it doesn't take a 2.5 THz giga-core system with an exabyte of RAM to load the website.