Re: Need a lightweight distro...
What is going to be the primary purpose of the machine?
That desire may drive your choice. Fedora in my opinion is no lighter than Ubuntu. You may want to Give Bodhi a try though it's based on Ubuntu 12.04 but uses the lightweight E-17 desktop which is very customizable.
There is always Puppy but I don't use it for security reasons here but it will fly on older equipment. and is passable in looks.
Good Luck I'm sure you'll get more suggestions.
Registered Linux User #462608
Ubuntu 14.04.1 /Xubuntu 14.04.1