I chose to be the first one to bite the Vista bullet mainly because I don't actually do a whole lot of work so if I am without a computer I can cope for a while. My main tasks use the following software: Office (particularly Outlook and Visio), Remote Desktop Client and a web browser. I figured that as long as those are covered I can keep on working.
I installed it on my Dell D820 and found that all the drivers were installed right away with no extra work on my part. This is pretty ace and although I am sure it's not the case with more obscure hardware, the mainstream peripherals have gone on OK as well.
Post install I joined onto the company domain and found that most of my profile was loaded and all the important group policies were applied. I have not checked what is different before/after but things like proxy scripts (the stuff which counts) all works fine.
I have installed a bunch of software and while most things needed an up to date version (Cisco VPN, Citrix client, Symantec Antivirus) the only thing that does not work is the media manager portion of the Blackberry Desktop software and I am too *** to try our whole disk encryption software untill I see the word Vista next to the latest version download.
I am loving the DVD creator software (my little brother is a keen actor) and the Media Center stuff (on another box at home with a TV card) and was impressed with the way it found the XBox 360 without being prompted.
All in all, although skeptical (yes I went through 95, 2000, XP &SP2), I have been very impressed with Vista and would recommend people look at it sooner rather than later (I was nearly put off by the "wait until a service pack comes out" mentality).
-me