Hi there, I am looking to upgrade my lens for my Canon EOS 450D to a better model and am interested in either:

Canon EF 24-70mm f/2.8 L USM
Canon EF 24-105mm f/4 L IS USM*

Now I am willing to spend the money on the lenses but am not sure it's worth it for the 450D model considering the small size frame sensor. I use this camera mainly when travelling for shooting 90% of the time during daylight, dawn or dusk. So I am looking for a decent lens I don't have to take off.

My current lens is the:
Tamron macro AF 18-200 F/3.5-6.3XR Di

This has served me really well, however I have found I don't really need all that zoom and the image quality is not great at the higher zoom.

Anyone have any thoughts. Thanks