The 35mm F/2 has the (in)famous "angry wasp" focus motor. It has never bothered me, especially in light of the optical qualities of the lens. The 85/1.8 is USM, but I'm not sure it focuses any faster. The main advantage of the 85 is that it has absolutely gorgeous bokeh. It has arguably the best bang-for-the-buck in the entire Canon lineup when it comes to background blur. Being something of a bokeh obsessive, this key for me.
Speaking of obsessive, Canon announced the 5D Mk II today. 21.1MP full frame, ISO 100-6400 (presumably in 1/3rd stop increments) and 12800 and 25600 in trick modes. I hope it comes close to the high ISO performanceof Nikon's D3 and D700, but I am not optimistic. Nikon wisely kept the MP of those two bodies at something sane. 20+MP is really not good for much except for filling up one's memory card and hard drive. Still, they're offering the 5D II with a 24-105L for just over $3000, which is the cost of a D700 body only.
Anyone want to buy a kidney?