Lesser Rune of Warding

This is yellow when learned at 325, green at 330 and grey at 335.

I recommend using this to skill up all the way to 335, contrary to most guides' suggestions to stop at 330. With Fel Iron much more expensive than Adamantite these days, the next leveling item to use is the Adamantite Cleaver. Even with this recipe green, you are likely to get more than one skill up per 8 casts. Thus this recipe can get you from 330-335 cheaper than an orange recipe using 8 bars each time.

Yep, these are the way to go for leveling your smithing. Went from 325 to 335 using only 24 adamantite bars. Make sure you wait til these gray out before making your specialized armor/weapon to take advantage of the rune skill-ups while maintaining the orange status of your armor/weapon. Then you just need 4 more skill-ups til you can start the process over with http://www.wowhead.com/?spell=29728 Happy skilling.