"I believe it is the best version of Windows Microsoft has produced. It's a boost to productivity and a pleasure to use. Despite a few drawbacks, I can heartily recommend Windows 7 to mainstream consumers."
If this were just hype, I wouldn't be passing this article from the Wall Street Journal along; but having used Windows 7 for a while now, I don't want to go back to XP. In my opinion, and the opinion of others I've talked to, this is the most "ready to go" Windows ever. You don't have to wait until Service Pack 1.
If you need a new computer and can hold out a few weeks, get one with Windows 7 pre-installed. If you are using an older version of Windows like XP or Vista, I recommend upgrading to Windows 7 if your equipment meets at least the minimum requirements and you are up to the task of doing the upgrade. This really is the best Windows ever.