Also Linux, Linux AMD64, Solaris SPARC, and Solaris x86 from Sun and OSX through apple.
A download of the JRE requires ~15MB of disk space for most of the platforms, but I sincerely doubt that will come close to 125MB unpacked. I think Kurt might have been looking at the SDKs.
You'll want to list how much random access memory and CPU your game uses, what the graphics and sound requirements are, if it's online you should state the minimum speed required, and how much disk space your program requires.
Edit: If necessary, you can get the amount of RAM your game + JRE uses from the process list in WinXP, I think Linux actually has a better one if you're using it