For those that may not have known this, even when you buy an "Upgrade" edition, you can still do a clean install, which is almost always recommended. The "Upgrade" bit just means that officially you need to have owned a previous version of Windows to be eligible. Some older versions would have you pop in an older disc to prove this, though I don't know if 7 goes through that.
At any rate, $30 is a great deal especially for professional!
If you aren't a student, but have 3+ computers, you might consider the family pack too. That is $150 for 3 copies of Home Premium.
7 really is quite a bit better than Vista, I have been enjoying it so far.