and towards the end I got one of the low-profile USB-powered drives.
Got of those, too (the early USB 1 ones, with the exposed ATAPI connector. I ended up buying Iomega's Firewire expansion that attaches on the back of the slim USB and latches on that ATAPI connector, as Firewire 400 had much better bandwidth than USB 1, provided enough power and thus required only a single cable, and I had a cheap Firewire 400 adapter laying around from some video project (funily: the Firewire 400 card was a free bundle bundled with some crappy movie software that was selling poorly and was on heavy sale at the shop I bought it from. Threw the useless CD, kept the Firewire card).
Actually I still have all three of them in storage now I think, and since one is USB I might be able to theoretically recover any data I have on disks still.
Mine still works too. The most difficult was trying to find the barrel power plug (since back in the days I was mostly using the Firewire attachment and because Firewire provides enough power, I wasn't using the barrel jack much. Nowadays most of my machine are USB only.
Zip drives were great when I first got into it
Yup. The slim USB were also a good solution to carry data around.
Bring the slim USB and the cables at the university, download shit with the fast bandwidth, then bring the drive back home, plug into the Firewire attachment and load it onto the computer.
Later the university aquired computers (from Dell) that came with ZIP IDE drive built in, so I only carried the Zip250 disks and kept the drive permanently plugged into the Firewire attachement. And almost lost the power barrel adapter as mentioned above.