If you can get another 128MB of RAM in that box you will see a big improvement. Swapping to the HD makes things slow down. 650Mhz is plenty fast enough to run Linux. I run BSD on a PII 400 and adding RAM makes all the difference. Make sure that you are using DMA access with the hard drive. hdparm /dev/hda
Try Flubox or similar for a WM.
Rox is a good file mgr but light.
Nedit makes a good light editor, Gedit is a little heavier but good.
Sylpheed is a good light email client.
Dillo is a good fast light web browser, doesn't render every page correctly.
Xmix, Gmix, Aumix make good lighter mixers.
Xnview makes a good light image viewer.
AbiWord makes a good lighter word processor.
Gkrellm, Xcalc, File roller, Xclipboard, Ghex, Gv, Ghostview, Aterm, Xterm, mc, are some more smaller apps you may want. Those are just examples.
This is for FreeBSD but it identifies what the app names are used for. Linux uses the same applications.
http://www.freebsdsoftware.org/
KDE, Gnome and a lack of RAM is probably why you haven't been impressed so far.