The R500 bit the dust over a year and a half ago. Most PC manufacturers were busy trying to crank out netbooks or a Macbook Air ripoff at the time, so there was no suitable replacement -- had to limp along with a Macbook Pro (ugh!) running Ubuntu until spring of this year.
What replaced the R500? A Thinkpad X1. It weighs twice as much, has no transreflective screen, and is a bit bulkier, but it is paradise after using that Macbook Pro for a year. Dedicated pageup/down keys! Home and End keys! A Delete key! THREE mouse buttons! A hardware kill switch for wifi and bluetooth! A freaken eSATA connector!
But why no grumpy install post detailing how to get Linux speaking to all the hardware? Because everything just works! Even the volume control buttons and the fingerprint reader. No joke. You can thank IBM's interest in Linux for that.
On top of the compatibility, it's a nice looking machine, powerful (64-bit debian runs great on a dual-core i5 with 8 GB of RAM), and tough -- GorillaGlass over the display, MILSPEC (assuming 810) shock and spill resistance (including a keyboard that drains *through* to the bottom of the laptop), the works.
The one caveat: it's best to use non-standard video drivers, as the standard debian/ubuntu Intel video driver became a bit crashy. Easily fixed, though, by adding the xorg-edgers PPA.