I would agree that guitar pro is a great way to keep you going, but I think lessons are a valuable aspect of learning. Just like anything, having 1 on 1 help, if good, can be a great way to continue to expand.
Lots of the best guitarists do take lessons. In fact before the black album came out for Metallica, Kirk went to the SF community college to study music, let alone his work with Satch. Randy Rhoades also took lessons while on tour. While many of these guys may not have started by taking lessons I think a good teacher can filter out the crap and focus you on the shit you need to learn. Also, lessons, at least for me, were not just scales. I was taught technique, rhythm, and different little tricks or accents that many of the old blues guys used a 100 years ago. But at the same time, with Youtube and all the free lesson sites online they can act as a great teacher if you're disciplined enough to work independently.
I took lessons for 2 months when I first started. They are expensive, but I think it was well worth my time since it helped me focus on base guitar skills so I could learn everything else more easily.
