I would not recommend Ubuntu full blown OS. It will require much more disk space and physical memory. You should check out Xubuntu, a variant of Ubuntu based on XFCE desktop or any other Ubuntu variant built on smaller desktop environment like LXDE. There is Linux Mint LXDE edition based on Ubuntu LXDE. Else you could try Dream Linux which also based on Debian just like Ubuntu but used XFCE, is easy to use, light on resources and still good looking.
Anyhow, welcome to LQ