I got a Sigma 18-200mm F3.5-6.3 DC (more information at
http://www.sigmaphoto.com/lenses/lenses_all_details.asp?id=3302&navigator=6) for the Canon 350D. It is my second Sigma lens, not because I am a Sigma fanatic LOL but because Canon (and Nikon too) does not make a 18-200mm yet. They do not even make a 18-125mm. For film slrs, 28-200 or 28-300mm lenses are pretty common but for digital slrs, only Sigma and Tamron make them.
I do not expect fantastic image/fast autofocus but for "tourist" photos it should be fine: it is small, light and the range 28.8-320mm on the 350D is perfect. It is not a fast lens but increasing the ISO does not really affect the photos with that Canon (from what I saw online).

Olly

I got a Sigma 18-200mm F3.5-6.3 DC (more information at
http://www.sigmaphoto.com/lenses/lenses_all_details.asp?id=3302&navigator=6) for the Canon 350D. It is my second Sigma lens, not because I am a Sigma fanatic LOL but because Canon (and Nikon too) does not make a 18-200mm yet. They do not even make a 18-125mm. For film slrs, 28-200 or 28-300mm lenses are pretty common but for digital slrs, only Sigma and Tamron make them.
I do not expect fantastic image/fast autofocus but for "tourist" photos it should be fine: it is small, light and the range 28.8-320mm on the 350D is perfect. It is not a fast lens but increasing the ISO does not really affect the photos with that Canon (from what I saw online).

Olly
Dear Olly, I have a 350D and I am very happy. The lens I have is the on that comes with 350D, a EFS 18-55. I think this is not a famous one. I am looking for a tele that can allow me to take diferent picture without to have the necessity to change lens. It seems that your sigma is a nice option.
Tks

I really like this Sigma 18-200 lens. It is so easy to take photos with it :)
The distorsion is low and only visible at wide angle (it has even less distorsion than the Nikon 18-70 that gets great reviews).
The Tamron 18-200 is better at full zoom than the Sigma but it has a lot of distorsion at wide angle according to the magazine Chasseur d'Images. The Tamron is made in plastic while the Sigma is in metal.