I'm now up and running with Ubuntu "Feisty Fawn" and doing very well with it.
With my previous "Edgy Edge" setup I had real problems getting the nVidia drivers for my Asus A7N266 motherboard configured correctly. Using legacy drivers I could get most things working, but I never did get Google Earth or streaming video on sites such as BBC News to be stable.
Upgraded to Feisty hoping that it would sort these issues out - it didn't. Struggled on for a couple of days and convinced myself that it was the A7N266's onboard GeForce2 video setup that Ubuntu could not handle.
Bought a new cheap video card (Tornado GeForce FX5200 for 30 quid), stuck it in the AGP slot - and hey presto everything now works absolutely fine.
RC
PS I dual boot with XP and have had no problems. Set up your NTFS partition as the first on the drive, and install XP into that. Then install Ubuntu specifying partitions 2,3,4 as Ext3 for Linux root, swap, data etc. The installation process should spot XP in the first partition and ask whether you want to set up GRUB for dual boot - say yes.