Hey guys,
A substantial part of my photography goes toward landscapes and architecture. So far I've been using the kit lens to do wide-angle shots, and I'm quite unsatisfied with the lens. It's pretty soft (the 55-250 is much sharper, I love that lens btw) even on my tripod, AF is not good in low light, hard to use a polarizer on it without moving the focusing ring, undesirable lens flare, etc. I've taken some great shots with it, but I'm looking to step up the game a little bit.
So here's the game plan: I eventually will acquire a full frame body for landscapes and architecture. But not now. The ideal lens to get would be the TS-E 17L, but wow that lens costs $$$$$$$ to me. So my options are to get maybe the TS-E 24L mark I, 16-35L, or 17-40L. Since I'm using a crop body right now, I would like to use this lens as a general walkaround lens also, until one day I get a FF camera. The f/2.8 of the 16-35L seems nice for a walkaround lens, but unnecessary for my landscape and architecture shots. Conversely, the f/4 of the 17-40L is just fine for my landscape and architecture, but not as great for walking around (several times have I wished that my kit lens were faster) and perhaps not as sharp?? Compromises. So, around the $1200 mark, would it be better to get the TS-E and lose the convenience of zoom and AF, the 16-35L, or 17-40L and use the price difference to get a flash or something? Other lens choices?

