<p>+1 on the recommendation for the 24mm PC-E for buildings, bridges and landscapes. I bought the Rokinon TS 24mm and it is a great thing to have. I kind of wish I had picked up the Nikon PC-E 24mm instead.</p>
<p>If you are going to to do a lot of wide angle work, the FX format is easier to work with for that, at least in my opinion.</p>