hmm... howis the 12-24 f4? i am thinking of getting it, because its FF compatible, and also because it IMO, is a great match to my 24-70..
12-24,24-70, means i have 12-70 covered!!
maybe you should consider this also... it's like in between the 10-22 and 17-40. f4, like the 17-40, and also ff compatible. i think i would choose this rather than 10-22, because you never know how cheap FF bodies may be in the future. also, can use with film SLR.