I've been dealing with this "graphical glitch" for a while now, it's really getting on my nerves. It used to be on my blocks too, but it got resolved in 1.4.7 or 1.5.1, there are small white lines on any item like swords, torches, iron bars, enchanted books, armor, bow, arrow. The weird thing it is not on some items such as spawner egg, ores like diamond, gold, also the dyes, leather, etc. Also, my friends have not had this "graphical glitch" if you want to call it that. I have tried installing Optifine to see if that would help, I've turned AA (anti-aliasing) on, then off again, still didn't help. I am using the ATI catalyst control center to view the AA options.
here is a screenshot of what I'm dealing with (via imgur.com)
http://imgur.com/K4hz1SD