I also really enjoy architectural photography. I've been doing research for a couple of months and this is the combination I've decided on for my needs: (I have a Canon xti, and I don't know what the equivalents are for Nikon.)
Canon TS-E 24mm f/3.5L Tilt Shift Lens
Kenko DG Auto Extension Tube Set
Sigma 12-24mm f/4.5-5.6 EX DG IF HSM Aspherical Ultra Wide Angle Zoom Lens
The tilt shift lens is expensive, but for me personally, it's the most important lens I can think of getting. 24mm is nice and wide, and with the extension tube set, you can make the lens effectively a telephoto of varying lengths and even (so I hear) use it for macro photography. Photo editing programs can help with perspective correction, but you lose data that way. Just something to think about.
The sigma is the widest zoom lens currently available for a full frame body. Personally, I like wide, and I find that when I'm shooting, wider is one of the things I wish for most.
Sigma also has an inexpensive telephoto, APO DG 70-300mm f4-5.6 with macro setting. It's a good lens, (the only one I've listed that I actually have) but I haven't used it much, personally. I guess it depends what kind of architectural photography you like. Do you find yourself wishing you could get more of the scene in the image or that you could get closer to specific details in the scene?
Anyway, I don't know if this is exactly what you were looking for, but I hope this helps.