I read this line, "I should eventually have a DX and FX camera that I plan on using together." and thought you planned to use a DX camera with an FX camera exclusively.
I have the 14-24 f/2.8 that is both a fantastic wide zoom and a PITA at the same time. I like the 20mm f/2.8 for a lightweight wide (I might get one for hiking use). The 16-35mm f/4 is really nice too. I typically use a flash whenever I use the wide angle for anything other than landscapes so f/4 wouldn't bother me much.