I use vimperator as well. it gives you the ability to follow links using the keyboard (same tab, new tab, copy link) as well as all the bookmarky shortcut stuff that gleebox does. Combine it with a keyboard based window manager (like StumpWM) and you can (almost) throw your mouse away!

I'm also a user of vimperator. I wish someone would port it to Google Chrome as I'm tired of beeing locked in to Firefox.

gleeBox and vimperator differ a lot in the way they work even though their core functionality is the same, that is to aid in navigation.

And, with gleeBox, you can do a lot more like search bookmarks, execute bookmarklets, yubnub commands, etc. Plus, I think it is more easy to use for the non-vim junkies :)

Searching bookmarks are available by default in vimperator. You can easily create a yubnub command and assign a hotkey for it, i think. And since vimperator can execute any javascript code from its command line, you can execute bookmarklets.