> what can I do, what can I run that will not use too much resources?
First of all, the most important, is the desktop environment. An old laptop
with limited resources may run flawlessly with xfce, and barely move with say
KDE.
I have used for a long time Xfce, I really recommend it. Some say LXDE is
faster, but last time I checked, I saw no difference at all. Xfce is IMHO
much more complete and customizable than LXDE, very easy to customize and to
make it look modern and shiny.
Then, the applications you run.
The browser is usually the heaviest one, firefox and most of its variants are
as heavy as it gets. I recommend seamonkey and Links2. Dillo is great too.
You could try some others (like netsurf, xombrero etc) and see if you like
one.
Nothing plays as smoothly the videos as "smplayer" does in my experience.
A very lightweight mail client (and great software overall) is claws mail
(too bad it constantly gave me issues with riseup :/ )
For the musicz: qmmp.
You could even go "half-full cli" and find a cli replacement for many of your
GUI applications (which is very fascinating and something I have been trying
to do lately).
Cli applications tend to be inherently more efficient in terms of resources.
