I've heard great things about all of them but I would say considering the price difference and the fact that they are non-L lenses that they probably aren't quite as good.
I've only used the 17 and the 24, but from what I read on other threads in this forum is that the 90 is better than the 45. Another thing to keep in mind is that neither the 45 nor 90 have the rotation joint between the tilt and shift functions like the 17 and 24 II do.
Me, too. And I've also considered 45 and 90 T-SE, but they are much older lenses, so I'm hoping Canon revamps them some time this millenium. If not, I'll probably pick up the 90, which is widely considered sharper than 45.