Not sure what the issue is, but I'm unable to get labels to display in ArcMap 10. The obvious things are accounted for (as far as I know). Labels are set in Properties, layers are checked to label in the TOC.
I've even restarted to see if that would work.
UPDATE: 3/3/2011
After trying all of the mentioned solutions, I was still unable to get labels to display. It wasn't specific to a single layer, but rather to any layer in the .mxd.
I opened a new document, added the layer I'd been trying to label, and was able to display labels just fine.
What may have caused the initial document to globally make labels not display?