I'm glad Tony brought it up...
Right or wrong, when I'm talking to ATC I always put a "K" in front of an "all letter" airport just to make sure they know I referring to an airport and not a VOR located at or near the airport. In some cases this could make a difference of 10 or more miles in your flight path. It's never good when ATC thinks you're going to point 1 when you're actually navigating to point 2 ten miles away especially when your on an IFR plan.
For example, I used to be based at KSGF & the SGF VOR is over 7 miles north.