Sun SPARCstation 2

The most base Amiga 1000's have just 256k of RAM and a single 880k floppy and require two steps to boot the OS (loading Kickstart off of the 1st floppy and then reading Workbench off of the second) and will happily run off of that single floppy, even allowing you to swap it out for whatever application disk you want to use. This with full GUI, sound and all the other nifty things that go along with using an Amiga. I no longer recall what the exact size of the A1000's Kickstart is but nearly all remaining machines (with the exception of a softkicked A3000) had the Kickstart in ROM. Of course, there was also the Atari ST line that had it's GEM-based TOS totally ROM based and ran well in less than 1meg of RAM, though I've never thought their graphics capabilities were on par with the Amiga.