If you haven’t already done so, have a look at the Gnome 2.22 release notes. As usual the latest release of Gnome comes with a lot of subtle improvements which are described and illustrated in the release notes:
http://library.gnome.org/misc/release-notes/2.22/
Although some of the applications that are part of the Gnome project aren’t included in Linux Mint by default, a lot of these upstream improvements will directly affect your user experience in the upcoming Linux Mint 5 Elyssa planned for release in May.