Since this question probably comes up alot, let this newbie jump in and test my understanding so the old pro's don't have a fit about "here we go again..."
Since you already decided to go with a new hub instead of living without a lockring and redishing and respacing your original hub you should probably go with one of these hubs, an IRO or a cogswell,
http://www.irocycle.com/id67.html
or
http://www.kogswell.com/
they're sightly more expensive than the Suzue basic hub that NYCBikes sells with that offer. The better hubs will come with sealed bearings and a higher quality threading for the cogs. Also make a note of your rear dropout spacing (distance between the dropouts) before buy your hubs, you should be able to respace (if the axle is long enough...) later if you happened to buy 120mm spaced hubs and your frame turns out to have 130mm spacing between the dropouts.
As far as which chainring to get rid of...it depends on the gear set you choose for your self. Here's one chart. Most people pick something around 70 gearinches, I think, to begin with (42x16 or 52x20 or 39x15).
http://www.fixedgeargallery.com/resources/gearchart.jpg
The chainline (measurement from center of the bike out to the chain, or chainring) is the important thing here, you want your chain to travel in a straight line between the front and rear gears other wise it'll have a tendency to jump off. So which ever chainring gives you the straightest shot back to the rear cog is the one you'll want to keep. You shouldn't have to replace the bb, unless it'll help you get a more straighter chainline.
good luck and have fun