Photozone.de likes the Sigma 10-20 f/4-5.6. It's obviously a hair slower aperture-wise, but it is a lot cheaper than the Nikon 10-24. They also really like the Sigma 8-16mm f/4-5.6 and give it their rare Highly Recommended rating.

35mm would be on the short side for a portrait lens; the 50mm would give you an equivalent 75mm.