I'm guessing this is what happened:
You tweaked your rim last season so you wanted to upgrade to something beefier. Once you had the rims picked out you decided that as long as you were getting new wheels built, you might as well upgrade the hubs. While shopping for hubs you started thinking that if you were going to buy some really nice ones you wanted them to last a while, so you better make sure you upgrade to a 20mm front axle. Finally, you ended getting a new fork that was compatible with that axle.
Am I close?

That's kind of backwards, but yeah.
I wanted the front end of the bike to have as much travel as the rear, plus I wanted a slightly steeper head angle. So I wanted a 160mm fork (the stock fork was 140mm). I figured if I upgrade the fork I might as well get a 20mm TA and bigger stanchions. With the new fork I would need a new front hub, but I wasn't in love with my wheels anyway so figured I might as well get some new ones. And if I'm going to spend the money I might as well get good stuff.
The rims were Frank's recommendation and they look pretty beefy. I wanted Hope hubs because from what I've read on MTBR they last forever and are super easy to service. Plus they're red which is pimp, and they don't cost as much as Chris Kings or Hadleys.
I briefly considered a Fox 36 Van R but it was almost twice as much as the 55R and the name doesn't mean much to me. I would've saved about 1 lb in weight but even still my bike only weighs in at 33 lbs right now.
My bike is nearing "done." Really I just "need" a new stem now, but I'd like to replace the brakes and crank eventually. Speaking of, you still want to sell me that BG?