Hey everyone, I have written an article on tweaking the appearance and UI of Lubuntu here.
Lubuntu is one of the most sought after Linux distro for low-resource or old hardware. It is pretty good, in the way, that it can get you the latest, updated software at very low resources(a decent desktop, at as low as 512 MB RAM(tested) and reportedly has even been used on a 64 MB hardware). You can run almost any Ubuntu package on it, without any hassle(I personally used it for 1+ year on a 1 GHz 512 MB RAM machine). Many also like running it on modern hardware, just because, well, they like it.
The main down point of Lubuntu, however, is its super-simple UI and feel. If you really like no-frills, then you should probably stay with that, however, if you love tweaking around, and want a better UX, then read on.
(This is what the default installation looks like)
I tweaked around a bit and this is what I could achieve -