Wide prime: 28 f1.8 vs. 35 f2

Hi all,

While one part of me is telling me to get the 50 1.4 for when I really want a crispy sharp picture with great bokeh, another part of me is saying I'd find more use of a wide angle prime for indoor available light shooting and/or landscapes. While I'm figuring this out, if anybody can offer any input on how these two wide angles comapre that would help a little bit in the final decision for a prime to accompany my 17-85. I'm wondering how these lenses compare optically in terms of color/contrast and sharpness, both to each other and to the 50 1.4, which I hear is really sharp. I'm also wondering how the two rate in terms of low light focusing performance, and specifically how bad the focusing noise is for the 35 (just how loud is it anyway?). Also, would any of these three lenses offer newbie-noticable sharpness improvements over the 17-85 IS I own and love, or are they optical equals and I'm just gaining a faster aperture?

Thanks guys!