I'm almost ashamed to say it, but Vista x64 is the winner on my Thinkpad

Granted, the only Linux variant I tried was Ubuntu, but since it's supposed to be one of the most consumer-oriented out there, I figure that's fair.

In all, I tried x32 and x64 Ubuntu 7.10 and 8.04, x32 MS XP, x32 Vista, and X64 Vista. My new t61p has an Nvidia Quadro FX570M, which MAY be the source of the problems with power management under Linux, but I don't really care - I'm not trying to be any sort of apologist. I tried all of the listed OS's, using all of the latest available drivers, and x64 Vista with SP1 (it's a fresh install available from MSDN) comes out the winner by far. Additionally, I find it VERY close to the performance of OS X!

The main functions I care about in a LAPTOP (the type of computer I use 95% of the time) are:

VMWare performance
Fast suspend/resume
As much RAM as possible
VNC client
High resolution display
Practically portable (17-inch is a little too large)

For all of the above, x64 Vista seems to match OS X's performance. Virtual machines resume amazingly quickly, and they suspend almost immediately. And right now I have the following applications open:

MS Outlook
Firefox (with quite a few extensions) - 12 tabs open
IE (seems silly, but some sites I have to use only support IE)
VMWare Workstation with 2 MS Server 2003 VMs running (one with 1.5GB RAM, the other with 1GB RAM); I'm running the ITM 6.2 server in one and WebSphere 6.1 in the other.
iTunes

And I'm having absolutely no problems.

From Task Manager, my Memory usage is at 3.75GB, and CPU is averaging 20-25%.

x32 Vista w/SP1 was also working really nicely, but I wanted to see all of my available 4GB of RAM.

Based on these results, I plan to install x32 Vista on my t60p (only has 32-bit Core Duo chip), replacing Ubuntu because I can't get suspend/resume to work correctly on it.

While I was PISSED at Vista when it first came out (that's what forced me over to OS X), it truly feels like it has gotten better with SP1.

Related topic: I installed (just put it in the adapter and slid it in the Ultrabay) my second hard drive, so I've now got a total of 520GB of on-board storage. I definitely like Thinkpads :)