I've got the 35mm 1.8 and a 50mm 1.4. The 1.8 is almost always the one on my D40 because I can 1. Autofocus, and 2. It's wider. Usually when I need fast glass, its because I'm shooting inside. On a DX, the 50mm is just to much focal length... Its no biggie if your shooting grand central station, but if your shooting a tiny dive bar, it makes it kind of tough.
Connor - Don't spend to much time regreting that SU-800 purchase. As a trigger goes, its superior to the D80\90's pop-up flash. I don't own one, but I've read it has a good bit more range. As an added bonus, you can aim it.
On the SB-600 vs. SB-600 Replacement - I say wait. The SB-900 has some flaws. It's too big, and some of them have a problem with overheating. It also has some big advantages - Longer zoom range, MUCH better controls, auto WB adjustment, oh yes, and it goes to 11. I expect the SB-700 (or whatever) will basically be a SB-600 with a redesigned interface, possibly more power, and a few other goodies. Wedding shooters don't shoot with a 600, so they won't be around to drive up the price.