I've been using Windows 7 for about a week now and I have found it to be a really decent experience so far. Quite fast, perfectly stable, and the new UI is useful. Interestingly, it only used about 8GB for the install vs. the 20-30GB that Vista ended up taking. Baseline memory usage is down about 22% from Vista.
If you're interested, it is perfectly legal (and significantly cheaper) to purchase the upgrade edition of Windows 7 as long as you have a legitimate copy of Windows XP or Vista. If you have an email address ending with ".edu" (typically a college/university provided one) you can get Home or Professional edition for $30.
I chose to do a fresh install, but if you have Vista there is the option of performing an in-place upgrade which will keep all of your files intact.
If you have been waiting since XP, then wait no longer; 7 is a great OS. I wouldn't worry about bugs or driver issues as it is almost identical to Vista "under it's skin"; I've heard you can even use the older drivers from Vista.