Originally posted by pingu I was thinking Sigma 30mm 1.4($500) until the point you brought up Sigma 18-35 mm F1.8 ($800)
is it worth shelling out $300 more for 18-35 or spend $300+ for another lens in 10-20mm range?
Sigma 18-35 mm F1.8 = $800
Sigma 30mm 1.4($500) + Sigma 10-20mm f/4-5.6 ($400)=$900
Personally, I would think the 30mm 1.4 + 10-20mm is a better option. Both are great lenses for their specific purposes (10-20 is sharp edge to edge for landscapes and citiscapes, 30 1.4 is super sharp in the center, great bokeh, 3D looking, for isolating subjects).
But you know what your needs are and what kind of flexibility you need - more range and better low light, or a single (big) lens that stays on the camera? Up to you to decide
If you are in that price range, by the way, don't discount the Pentax 20-40mm DA Limited. In my humble opinion it produces stunning images, much smaller than the Sigma 18-35, is WR and can be found quite discounted these days. It's my dream lens nowadays.