My current desktop system is no slouch: a 2006 HP a1483w with dual-core AMD, two gigs of RAM, and built-in Nvidia graphics with 256 MB of shared memory. Hey, with two gigs, there's plenty to go around.

A gamer would sneer at it, but it's more than powerful enough to run Ubuntu Intrepid with a VMWare 2.0 Server XP machine running 24/7 in the background.

Sometimes, I run my 2K machine virtually, too. And all three systems coexist nicely with barely noticeable speed hits.

But I have decided to purchase a bare-bones system and build it up from scratch with Ubuntu.

Good installation howto for ubuntu linux on the lenovo thinkpad t400.

working out of box:
What works out of the box?

Wireless with iwlagn driver (Intel WiFi Link 5100/5300 WLAN controller)
G mode + WEP and WPA2 PSK (If you have the ThinkPad 11b/g Wireless LAN mini PCI Express Adapter III (Aetheros Chipset), see below!)
with status LED and everything!
Bluetooth
Even with Bluetooth Laser Mouse
Bluetooth can only be toggled together with WLAN on and off, to add a bluetooth-only-toggle (Fn+F6) that doesn't affect WLAN take a look here.
Intel Gigabit Ethernet Controller

Howto install fedora Linux on a lenovo thinkpad t400:

As you may have read earlier, I mentioned that I was excited to get Fedora 10 up and running on my Lenovo T400 laptop. This has proved a lot more difficult than I previously imagined. I actually discovered more problems and inconveniences that I didn’t intend on dealing with. I am going to put a list of these frustrations and how I solved them (most of them anyways).

This checklist was prepared a long time ago, when Linux was still in its infancy. Many of these questions may not be needed now, since modern Linux distributions can automatically find the answers.