With my regular practise over the last couple of months I can now play power chords, Minor pentatonic scales and techniques such as hammer on, pull offs and bends. I listen to mainly classic rock and Heavy Metal bands such as Deep Purple, Sabbath, ACDC, Motorhead and Judas Priest. For some reason I always feel that I should try and play songs by ear rather than sticking to tabs. Any tips on which band's songs should I start with and how to learn play songs by ear quickly?
A good way to start with learning by ear is actually trying to pick out simple melodies, like advert jingles or whatever. Learning things by ear is easy enough once you have the basics down but it has a learning curve like hitting a brick wall at first.

It will also help if you learn a little theory, knowing the notes in a key and how they relate to one another in terms of sound will help immeasurably.

Black Sabbath would probably be the ones I would go for first, the riffs tend to be quite simple and easy to pick up once you know a couple and you get your head around Iommi's style a bit.