Re: organizing my system
Did you try Xubuntu, since you have experience with it? 2 GB RAM should be enough to run it. Xfce can be blazing fast with enough RAM (> 1 GB). You can also try out package zram-config, a RAM compression scheme for those heavy tasks.
Cairo-Dock can be made to run without compositing by enabling 'Fake Transparency'. Don't know if it makes the system any slower but it looks fine.
Alternate fast OS: Bodhi Linux, Crunchbang.
husband@wife$ make sandwich
husband@wife$ sudo make sandwich