NeHe's guides are pretty well recognized now to be damaging to beginners. The code is sloppy and encourages copy-pasta coding by failing to properly explain the purpose of the code it provides. I really have to recommend against the NeHe guides.
The NeHe guides get you up and going quickly and provide a base for easy experimentation. That alone makes them hugely useful, I believe. The code is horrendous and there's often a lack of explanation, but it's very easy to take the code and play around with it. They're certainly not the thing to read if you're looking for best practices, but they give you the ability to hit the ground running.
If read in order (at least the first dozen or so), the NeHe guides do explain the purpose of each line of code with reasonable clarity. A decent programmer who is a beginner at OpenGL can use the NeHe guides to get started. I'd agree, though, that a novice programmer should have some additional guidance if using NeHe to learn C programming and OpenGL.
