This thread in the Arch forums introduced me to some new lightweight applications.
In particular, I find epdfview and Mirage helpful, since they can easily replace the Gimp and Acrobat Reader for my purposes.
Geany is mentioned, although I don’t think it will take the place of Leafpad for me, since it’s more for coders than just editing text files. It has a lot of features that would just get in the way for me.
I like that urxvt (actually rxvt) is mentioned, along with Graveman; I use those already.
PCManFM is in the list, but it has fallen out of favor with me lately, because of the need for FAM or gamin to be running as a daemon in order for it to function. I’m not real keen on that, particularly when Xfe does the job just as well, and doesn’t need prodding.
P.S.: I feel obligated to include this page, although most of the applications it suggests are a little too lightweight for my tastes.