I really missed clipboard managers when I switched to Linux years ago. The one in KDE is pretty good, but I have switched to Gnome. I tried Glipper and Parcelite but didn't find they had what I wanted.
I decided to try an write one myself, using Python and pyGTK. It's coming along nicely, and has features I wanted but couldn't find:
Snippets, with categories, tags, & icons in history menu. Optional title for a snippet (or clip).
Auto appending clipboard contents to a clip.
Create a new clip.
Load a file into a clip.
Save a clip to a file.
A simple plugin architecture allows extra functionality to be added by writing it in Python. I currently have plugins to:
delete blank lines.
dump snip category to a file.
email a clip.
explode a clip into several clips.
open URL's in a clip in browser.
post clip on PasteBin.
remove text via a regular expression.
remove HTML-XML tags.
remove leading characters.
remove line numbers.
shorten a URL.
Data is kept in a SQLite database, so each clip/snip has properties like date created, last used, times used, title, source & note.
While far from perfect, I find it very useful even at the present stage of development.