Personally, I’d go for GLUT. It’s so easy to use, it’s simply ridiculous. What’s more, all the examples from The Red Book–which, by the way, is required reading–use GLUT; so it’s a pretty good match.
I just wanted to let you know how smoothly the transition from GLUT to OpenGLUT went. I was able to drop it into some projects by changing only a single header; everything worked without a single line of code changed. And while I haven’t had a chance to peruse the documentation, it looks to be quite extensive indeed.
My only regret is that I couldn’t stop playing with that infernal glutWireSierpinskiSponge!