Another option you might consider is QNX. This is another UNIX clone (aka:linuxlike) that does a full install on a 500MB drive. Stable, fast on less endowed systems even with onnly 32MB of RAM or even less.
On a performance (boot time), QNX on a low end P-133 with 32MB of RAM had the system at the desktop in under a minute.
However, I found the "voyager" browser to be sorely lacking and Mozilla was a a better/more compatible browser.
Here is the download site for both the full install and the "amazing floppy based" QNX.
www.qnx.com
A side note here:
They call it the floppy based QNX "amazing" and it really is.
Includes network support and surfin!