Xubuntu is pretty easy to use.
Take your personal preference of distro. Whatever you're comfortable with.
These threads shouldn't be "which distro for xxxx", they should be "which window manager for xxxx". The distro makes no difference, it's what you're running that makes it "beefy" or "light". As you can customise any linux distro by adding (or removing) anything you want, choose one that you feel comfortable with and change the WM. Job done.