I only ever bought one guitar from a store and that was back in 93. All of my current guitars have been bought offline. I guess it's sort of a crap shoot, but if you go to a store and listen to the same model you want to purchase then you should be ok. And listen to reviews on Harmony-Central.com I've gotten some great guitars online and some were just ok. Funny thing is, the ones that were just ok were from the major brands. The one thats great is from some little company down in Texas. If you're buying used
1) Get pictures
2) Find out the guitars history
3) Why is the person selling it
4) What modifications have been done to it
5) Does it come with an amp or case

You can get some damn good prices online used and new. Shipping sucks though if you live in Alaska, Hawaii or Canada