I currently have Vista SP1, but I started with Vista not too long after it was released, and other than driver difficulty due to choosing Vista 64bit, I've had no complaints. Far better than XP, and I used XP for years. XP was easy to screw up, and my XP installs would BSOD at least once a month.
I think I've encountered 1 BSOD since installing Vista. It's stable as all hell, absolutely love it.
While my main PC was down, I was using my laptop. I performed an upgrade install to the Windows 7 beta. Holy shit, agreed - that is what Vista should have been. The taskbar is amazing, the OS in general is even more intuitive, and is very stable. Application compatibility is a little off at the moment, but I've been able to do basically everything I want to on it. Now that I fixed my main PC, it's hard to resist upgrading to W7 Beta. But with this system, and with all the apps I use on it, I don't want to risk application compatibility just yet.
But with RC1 releasing in a few months, I am definitely betting on W7 hitting retail before the end of the year, and I actually expect it in the Fall, maybe September or October. And I was expecting that before they even mentioned the next beta being a Release Candidate. Since it's built on the Windows 6 kernel, I knew it wouldn't take a ton of work to make the new OS work, unlike building Vista from scratch (building the 6 kernel), which was a total rebuild of Windows. But an awesome and worthwhile rebuild, an extremely capable kernel, and thus I am stoked for W7.