Trying to decide on a library for creating a window and capturing user input for my OpenGL app, but there are just way too many choices:
We have had rather good experiences with ClanLib 0.8 in 2008 and ClanLib 2.1 in 2009 on our C++ course. The productivity of the students (as measured by the quality of their project works) has greatly increased since switching over from SDL. However, it needs to be noted that 2.1 is still very incomplete and one will certainly run into features that are simply not implemented yet.
A couple of groups used Irrlicht (3D engine) with good results.
SFML looks promising, but I haven't had a chance to try it yet.
As others have stated, GLUT is not really suitable for anything serious. The rest of the libraries mentioned are something more of GUI toolkits than game development libraries.