The Ultimate Achievement

Now I'll admit that thought about quitting WoW. Once. That never happened. I have always played WoW solo. I have a couple RL friends that play, but their time is very limited. Most of my time is spent running solo. So, I mean, how could I quit WoW without obtaining the Ultimate WoW "Solo" Achievement. Loremaster. Here I am chasing achievements like Frostbitten and What a Long, Strange Trip It's Been...

What do you think is the Ultimate Wow "Solo" Achievement?

P.S. I think that I was probably 75% complete for Loremaster with the old world quests - prior to Cataclsym. Yeah, so I really should have finished it *sigh* Oh well, I've started on this achievement already and I'll keep ya updated on my status.

So far, I went back and finished what was left of Northrend and currently finishing up a lot of quests in Outland. Man, seems I basically skipped most of Outland. I should almost have The Seeker title once I finish Outland. BTW... My DK already has the Loremaster for Northrend and Outland complete.