Ones I've heard of (but I've never used one): Eclipse (www.eclipse.org), KDevelop (which I imagine you could use in a Gnome environment), Kylix from Borland, CodeWarrior from Metrowerks, Redhat's Source-Navigator, Dev-C++ from BloodshedSoftware (also on Sourceforge), Moonshine from Suite 3220, Code Crusader by John Lindal, all the ones in the Google Web Directory: http://directory.google.com/Top/Computers/Programming/Languages/C%2B%2B/Compilers/ Plus just the standard searches on Google.
But, like I say, I don't use them (use Emacs instead), and can't comment on any of them. Andrew.