Definitely Pclinuxos and Sidux.
Also consider Sabayon (3.5 final due out in a couple of weeks), and Mandriva. Yes, I'm kde biased
For small xfce distros there is the aforementioned Kateos which I haven't looked at in some time, and Vector and Zenwalk.
You might want to wait until Pclinuxos 2008 final comes out - although no one knows when that will be
. The current main install cd is over a year old and the updates are huge at this point. The 2008 mini is good but very limited in applications and I think is already a couple of months old. (My memory isn't too good here). You will get a better take on this distro with 2008 final.