I already ran XFCE 4.6 in Ubuntu 8.10. So I installed XFCE under Ubuntu 9.04 and it was quite smooth. Personally I am more at home with Gnome but XFCE seems to be quite functional and responsive.
There is a Chinese Live CD distro based on Xubuntu (along with LXDE) : Hiweed Linux. The 2.0RC version is based on Xubuntu 8.10. Maybe
it should instead be based on 9.04. Hiweed added ibus and ibus-pinyin and some other Chinese addons to Xubuntu.