I've taught myself now for 15 years (with a break of 6 years in the middle with no guitars at all!) - however, I did get a few lessons when I started from an amazing virtuoso player (he writes movie scores now and orchestrates for national tv). He showed me everything I needed to know re the mechanics and technique end of things but most importantly, he showed me how to use my ear properly. I was already grade 5 on the piano (Mozart, Bach, Beethoven etc) so I knew about 'tones' and arpgeggios etc but knew nothing about modes or exotic scales etc. I learned all of that by ear using the techniques he showed me and that is still the way I do things. That was the most invaluable lesson of all.
I lost interest in lessons when he started to introduce theory which is a pity I suppose, then again I'm happy to have developed my own style which works well for me. My advice is to only get lessons from a truely brilliant guitarist who really knows what he is doing. You'll learn what you need to very quickly from someone who is genuinely talented, then when you have the basics down properly you can decide how far you want to go into the theoretical end of things (if at all!).
Hope that helps.