Most distros offer a choice of "desktop environments" and/or "windows managers."

http://en.wikipedia.org/wiki/Desktop_environment
http://en.wikipedia.org/wiki/X_window_manager

My recommendation is to choose a distribution based on such factors as: stability, size/quality of software repositories, easy install of your favorite applications, quality of support, friendliness of community, frequency of updates, hardware support, philosophy, etc. (whatever factors are most important to you) and then find out if they offer your favorite DE/WM.

Here is a nice comparison of DE's from the Arch wiki:

https://wiki.archlinux.org/index.php...op_Environment

Here is a good comparison of the top 10 distros:

http://distrowatch.com/dwres.php?resource=major

You have some good suggestions, so I recommend to create some Live USB's and take a few of the recommended distros for a test drive.

LXDE is nice and lightweight for netbooks, and should be available for all distros. I'm using it with Slackware 14.0 on my eeepc 1001ha (Atom N270). I have boosted the RAM from 1 to 2 GB, but LXDE should run OK with 1.

I have installed Lubuntu on an 'old' laptop, and it's really lightweight and fast, without being 'minimalistic'.

I think Fuduntu is right choice for that type of machines. It easy to setup and very light with all required application at your hand.