My option is also not listed. I'll upgrade to Win7, if only because the time has come to try something new. But I won't rush off to the computer store today to get me a copy. I'll probably upgrade when:
1) I find the time to do so (might might be the biggest problem in the end)
2) When my XP install calls for it. (this could take some time though, XP installs are not so unstable as they once were - I could easily do a couple of years with the same install)

So yes, I'll move to Win7... when the time calls for it. Mind you, this is a radical change from Vista, which I wouldn't touch even with a 10 foot pole. At least I'm considering 7.