"So I guess it really comes down to whether I want MorphOS or OS4 then, right?
I'm not really sure which I would prefer at this point. I'm not planning on running any older amiga software, so I don't really care about that aspect of it. What I really want is a machine that has at least one OS that is mature enough to do everyday tasks (web browsing, a bit of C programming, some basic graphics editing, etc.) and several other OS's to dink around with."
Well that made it very easy then: neither MorphOS or OS4 is for you, as you can't live even a day without old Amiga software.
Linux would be your choise then, on the other hand that is {bleep}e on A1, so we come to the conclusion that Pegasos is for you. Njet.
From there we continue and remember that you can run Linux on x86 much cheaper and better, so there you go. And as a bonus you can also run Win Xp if you want.
Your choice is everyday home-pc.