But started deploying Windows 7 with no real headaches and a lot of tangible improvements.

Servers, we went from W2k to W2k3 to W2k8.

XP is dated and difficult to support and more prone to problems than Win 7. I'd prefer to have a complete OS recycle and get rid of Win XP... but it works well enough that the cost justification isn't there.

While your advice isn't unsound - I don't think it is a hard and fast rule that 2 years is the time you should wait before adopting. You should enter into any new OS by any vendor with caution - I don't think it matters if it is a *nix, OS X, one of the mobile OS platforms, or a Microsoft platform. Evaluate, test, solicit feedback from the industry, and go in with an informed opinion. Windows 8 is a major departure - so for business I think it requires an additional level of caution over a normal evolutionary upgrade of an OS. But if it caught on quickly and established a solid business case, I wouldn't want to be 12 months behind the industry.