1. jdesk
2. Dynamp, cause it supports both foobar and winamp.
3. using taskbar3 right now n mytheme, but I haven't tried xtaskbar yet, which seems to have a lot of features.
4. VTray
5. I just use a digital clock made with either xlabel or lsxcommand, depending on my needs.
6. Popup2

Of course these are mostly personal opinion...