Thats really a personal choice. If you want to learn GUITAR, then tabs suffice. If you want to learn MUSIC, then sheet is good to know. Its all about how much effort you want to put into learning the skill. traditional music notation is universal language to all instruments and tab only good for guitar (not that it cant be transposed and what not).
^ That.

Also, if you ever wanted to make a living as a session musician then you'd be expected to be able to see a sheet of notation and play it, so sight reading 'real' sheet music would be vital.

For me though, I've been playing almost 30 years and have never felt my inability to read sheet music has held me back.
Gibson LP Traditional, LP GT, LP Studio, SG Standard x2
Barber Tone Press > EHX Worm >TC Polytune > EXH Glove > EHX East River Drive > Zoom G3 > TC Spark Mini Booster
Jet City JCA22H
My SoundCloud
Last edited by GaryBillington at Apr 24, 2013,