All of those things work great on my x220.

All of those things work out of the box on my T420s

Yes, all those work on my new T430s. Just be sure not to get a model with NVidia graphics.

Joining the chorus of positive feedback, everything (including all things you specified) work out of the box in 12.04 on x61s.

To be fair, there is a known bug in resume from sleep/hibernation, but it is not particular to ThinkPads but to Intel GPUs.

External monitors are still annoying in my experience, and the only problem I had with sleep was the VirtualBox kernel module causing issues (though you can, if you're willing to edit config files, unload it upon suspend, avoiding any issues). Apart from that, I've not had much in the way of issues with my T410 over the past two years.

My expirience (x201 Lenovo laptop) with external monitors is excellent. I use 'grandr' for setting up the VGA display and I'm used to work with the maximum resolution supported by the laptop (2048x1536) and works smoothly and fine.

Sleep mode and WiFi works natively too. I have had some problems with hibernate mode but I'm not using anyway. The only think you cannot use under Linux is the fingerprint reader. Everything else works like a charm.

Oh god, you just reminded me of one of my biggest OS X gripes (before the iOS assimilation and lawsuits).... clam shell mode. What a PITA trying to invoke that was.

haven't tried external monitor, but yes to the other two.