You can go a long way with just knowing the major and pentatonic scales. The blues scales are basically pentatonic with two extra notes... so they're not that different. The biggest thing is not getting caught up in other peoples music because you'll end up not having any chops of your own. Try to get some exercises off this site or out of Guitar World magazine that work toward building your own chops. This way you can learn to improvise early on. Jamming is the best part of being able to play. Definitely look into some old Metallica stuff. "Fade to Black" is a great song to learn because it incorporates chording with some good riffs and some nice lead work as well. If you want to get challenged in the Blues arena take on some Stevie Ray Vaughan... he'll teach you a lot about chording all over the fret board as well as how to fly around the pentatonic scales and bend notes like its your job... for good tabs go to www.ultimate-guitar.com they have a great selection as well as some scales and such. Search for "online scale database" or something of the sort on a search engine and you should be able to find a site with scales. If you want to really get into scales check out the Guitar Grimoire books. They're massive scale books with more scales than you can imagine. Good Luck