Originally posted by Kronx
Forget websites, tapes, or your cousin Paul or any other half-ass way to learn. Take CLASSICAL guitar. Who cares if you want to play another type of music. If you do this you will be able to play anything you can possibly imagine, and play it well at that you will.
Honestly, learn how music really works. Don't just get to the point where youc an slap a lame melody over four chords and think you'll be able to sleep at night. If you want to be a musician, it must be your JOB. Treat it as such and don't settle for anything less than the best.
(And if you make it. I expect a thank you in the liner notes 
)
This is the best advice I have seen here. To crystalise what people have said; bad habits are easily learned but can take months or years to correct.
Classical lessons will help you a lot. However, I would suggest getting a good teacher and work on a more jazz oriented approach. Playing jazz seems to me to be the most fluid and dexterous type of music, it allows you to do so much more than cramming a natural minor melody over a natural minor progression, or thinking that using the lydian mode over a II, V, I progression is adventurous.
I fail to see how anyone interested in making music won't be interested in how it works.
Even if you're not too serious about playing guitar and you only want to bang out 3 chord tricks, lessons will get you to the level of competence needed years ahead of what you could do by stumbling blindly around on the internet or being roughly guided by some gimmicky tape.
Tapes, online lessons, tab books, all of that stuff, they should be seen as study aides, not as complete lessons.
But remember, not every guitar player is a good teacher. Even the fantastic Frank Gambale's video shows this. He is an amazing player, but a horrible teacher.
Find a decent school to study at that has passionate teachers who are accredited and know what they're talking about. Sure, it costs money, but so do tapes and books, and you'll get a tailor-made approach from a tutor which you won't find anywhere else.
Plus, good teachers will target in on your problem zones and work through them with you.
And most importantly, make sure you're having fun!!
