for me it's so i can run stuff that doesn't run so well or at all in dosbox.

My retrocomputing habit started with an SGI Indigo2 and quickly grew. For me, it was a chance to possess the ultimate high-end graphic workstations that I lusted after as a kid during the 90's. From SGIs I expanded into Macs, Suns, and older PCs, mostly out of curiosity. Computers had a lot more character in the 80's and 90's, before they became genericized, disposable, mass-market appliances.

The one common element that all my systems share is some graphics capability, which has always been my focus. Pure text-mode computing has never interested me much, so I'd probably avoid most systems from the 70's and early 80's. Just a personal preference.