Sorry, I'm no use to you there, I've played with a few Linux distros on VMs and Pi but never taken the plunge and lived with one on my main machine. I'm too heavily integrated into OSX/iOS to change now!
I think NOOBS comes with Linux Mint Debian, which is supposed to be lightweight, but I must admit I got bored with it after a short while. There was a RISC OS on there too, which was purely a nostalgic gimmick to me, taking me back to my youth on acorns!
The newer Pi has beefed up processing doesn't it, so should be a winner anyway.