New lens, help needed!

[d0051m]

Landscape and Cityscape? You can't go wrong with this: the EF-S 15-85mm http://www.amazon.co.uk/Canon-EF-S-1.../dp/B002NEFLDM

The 24-105mm won't be wide enough for a lot of landscape shots on the 450D, and the 17-40mm I don't think gives enough zoom range.

The Tamron 17-55mm f/2.8 non-IS is highly regarded too.

With the tamron being less than half the price of the canon 17-55 does the image quality suffer a lot?

[neuroanatomist]

With the tamron being less than half the price of the canon 17-55 does the image quality suffer a lot?

FOrgot to add above, but to be clear the Tamron is 17-50mm, not -55mm. You lose a little IQ, but not too much. You do lose IS, obviously, and the IQ of the Tamron 17-50mm VC (their version of IS) is worse.