I thought it was the lifetime of the author not of the owner of the copyright. Therefore, the lifetime of the corporation should not relevant.

Most of your problems seem to be from the OEM not Vista specific at all.
I got a Fujitsu tablet T4215 with one 1GB RAM with Vista Business pre-installed over 14 months ago. Recently upgraded the RAM to 2GB mainly due to the Firefox nightlies cloggin up the RAM.
1. Have not had any issues with the Firewall or Symantec (have corporate version instead of Norton). Only serious reason to see the UAC was the daily Firefox upgrades - but even that is gone now since that code has been fixed.

2. The power management has always worked out of the box and is much more informative than my earlier Fujitsu with XP - not sure whether to give MS or Fujitsu credit for this.

3. Never had an issue of overheating. The power saver mode actually reduces maximum processor speed to 50%. And this can be changed under the advanced power setting options.

4. Not enamored by IE7 - but do need to use and have never had a problem with it.

5. Wireless UI has become a lot more user-friendly compared to XP and it has been flawless in my experience.

The only serious issues I had out-of-the-box was
(a) the in-built card reader was not SDHC compatible - which Fujitsu fixed many months later with an upgrade.
(b) The delete/copy stuff takes too long. Personally, I think it is still pathetically slow.

Having said all that, I think if I installed XP on this machine, it will probably run faster but
(a) For most purposes, I am the rate limiting step on the computer right now so not sure if putting XP would help.
(b) I don't expect newer versions of software to run faster than the older ones. As hardware gets cheaper, there is little benefit developers and users derive in most scenarios by optimizing code infinitely. Plus newer versions typically do more things than older ones do. e.g. Office 2007 is significantly slower than Office 2003, but its drawing capabilities and live previews and the ribbon grouping has improved the overall experience considerably.

And this has been my experience with most software. We still have a couple of iMacs that used work before I upgraded to Tiger and they slowed to a crawl and everyone stopped using them. I know...I know...I shouldn't have upgraded them if they were working but it was getting difficult to maintain different software versions on different machines and I fell for the usual hype that OS X gets faster with each upgrade. Dumb me!