My favourit Linux Distribution is Linux Mint.
It is based on Ubuntu. But in my opinion the problem with Ubuntu is, that you are a bit constrained. Ubuntu One, and all the things Ubuntu programed into Gnome..I dont like it.
In Mint, you have the same comfort like Ubuntu, but you are totally free and you can use whatever you want.
In a few days a new Mint will be released. I totally looking forward to it! It will use Gnome3 as the default desktop. (Gnome 3 was released a few weeks ago)
At the moment, im using Ubuntu 11.04, with gnome 3. But Gnome 3 doesnt work very well with it, at the moment. Think it still has to be programed a bit.
So im really looking forward to Linux Mint 11 Katya!