For reasons unknown to anyone outside Cupertino, Apple handicapped their previously wonderful Digital Color Meter utility in Lion. Many folks are probably unaware of its existence, but Digital Color Meter, which resides in the Utilities folder, was great for locking onto a pixel and getting the hex code or just about any other color syntax. I used this all the time.
But Lion's version removes nearly all of its usefulness. I was pretty peeved when I went to use it and it didn't work for my usage anymore.
Thankfully, there's an app for that. A developer named Ricci Adams made Classic Color Meter and put it on the Mac App Store for a buck. Let me tell you, that is a buck well spent.