I spent a big chunk of this weekend reconfiguring my Eee PC. The Xandros install was just a bit to "funky" for my tastes and I kept running into weird limitations (like only having one login). AsusTek did a good job of customizing it to make it easy for Linux n00bs, but it was just a bit too stripped down for my tastes.
So, I slapped XP on the internal SSD and then installed Ubuntu 7.10 "Gutsy Gibbon" on a Sandisk 4 Gb SDHC card. I had surprisingly few issues, but I'll go through them anyway.

That's my new Grub bootloader screen. Ubuntu by default, XP if I wants it.
The XP install was pretty straight forward. I did a base XP Pro SP2 install, then removed a bunch of the accessories (screensavers, wallpapers, games, etc) and extra bits (MSN Explorer - ick) to save some space on the internal 4Gb drive. The only real Eee specific stuff I did was to install the drivers from the Eee support DVD and turn off the swap file. Everything worked well, but startup and shutdown were a bit slow and there was a fair chunk of memory being sucked up. I started picking through the services and set a bunch of them to manual to speed stuff up. I guess I got a bit too aggressive, because the Atheros wireless util and Activesync started freaking out. I re-enabled a few Com+ and DCOM services and they are now both functioning. The Atheros stuff works fine (it would just GPF earlier), but Activesync is still a bit upset about smthng. It works, it just complains about serial and infrared ports being missing. I'll tackle that later.
I'm actually going to redo the whole XP install anyway... I accidentally used an expired MSDN copy I had laying around and it won't activate. Oops. Nevermind, it'll at least last long enough to get me through my vacation before I have to fix it. I'll probably redo the whole thing with an nLite install
The Ubuntu install wasn't quite as easy. It's easier than I expected, but there are a few "gotchas" and some minor h@x0r1ng was required. Basically, I slapped in the 4 Gb SDHC card, booted of the Ubuntu live DVD and started the install. The only real customizing you have to do for the install itself is to change the partitions to use the entire SDHC card as the root volume ("/") and format it as EXT2 (although there's some online discussion regarding JFS being safer for flash drives - I may try that later). Ubuntu will complain about not having a swap partition, but it works. Finish off the install, then go fix some stuff... I distinctly remember having to customize my fstab file to set all the partitions to noatime. I also added all the temp and log directories as tempfs so they weren't writing all the time - although you might want to set up a script to save the logs on a shutdown. There was some minor customization of the interface required - turn off constrain_y so you can move big dialog boxes and remove the dropshadow effect (it causes weird screen flashes sometimes, particularly in Firefox's fullscreen mode). For convenience and to get more screen real-estate, I reset all the font sizes to 8 and installed the LittleFox theme for Firefox. Oh, also don't forget to grab the newest release of the Atheros madwifi drivers to support the onboard wireless. That gets rid of the need for ndiswrapper, which beats the snot out of your CPU and battery life.
There are still some small issues, but they are bearable. The standby mode doesn't work and I'm not sure if the webcam works... others have reported problems under Ubuntu, but I haven't tested it yet. Eventually, I'll come back and put in links to all the fixes I had to do. In the mean time, just go to EeeUser's Wiki and check out the Installing Alternative Operating Systems articles... they can run you through it.
Back to the XP side... I installed Activesync just so I could use my Blackjack as a shared internet connection (sorry, no links to AT&T sites until they give me my Windows Mobile 6 update). I tested it last night via the USB cable and it worked like a charm. I also set up a bluetooth PAN this morning on the commuter train and it also worked great. I downloaded Skype (21.5 MB) during the commute and was able to average 40Kbs on the download speed. I need a smaller bluetooth adaptor that I can just leave plugged in all the time, but it's good to know that it works. I'll tackle the same connection on the Ubuntu side of the house later.
Anyway, that's it in a nutshell. The Eee now rocks! It does everything I need it to do, can connect using Ethernet, Wifi, Bluetooth, USB through the phone, whatever. I basically have interwebs everywhere. :)