Like the friendship bracelet, I think the best friends necklace needs to be brought back. I vividly remember my first bff necklace I shared with my friend Jill, in 5th grade. She was mormon (as were all my friends back then, to my athiest parents dismay) so the necklace had some mormon scripture on the back. Hilarious. After an exhausting search online, there are a lot of shitty cheap versions out there, one hideous Juicy Couture version that comes up all over, and 2 fantastic versions worth a damn:
Best Fuckin Friends Necklace (this has been popping up all over the blogosphere)
I think some of the great jewelry makers with etsy stores need to get on this trend, stat.