What would be the best canon lens for night photography?

Im looking to get an affordable lens for the Canon XT to do some night photography. Preferably within the less expensive side. I'm going to Japan and would like to capture some good photos of Tokyo and Kyoto in a night setting. Can anyone recommend me some ideas? Tips, lenses, etc.

the 17-40 or the 10-22 would both be excellent, if you want to save some money the 50 1.8 is also an excellent choice. Don't forget to bring a tripod, you'll need it for night shots.

Something fast ... f/2.8 or faster, although I use my 12-24mm f/4.0 when shooting at night downtown in any world city.

Just shoot the way you do when you shoot at night. Just because you are shooting in Tokyo and Kyoto really is not different than anywhere else.

The Cannon 50mm f1.8 is cheap (probably less than $80) and much faster than most zooms. It seems to get good reviews, though every one says it's cheply made, it seems to be sharp, and for the price a good deal. For about $400 you can get almost another stop of speed (f1.4) and bettter construction, but you asked about the "less expensive side"

I second the vote for the 50mm 1.8 lens. Yes, you want to be careful not to drop it, but for the price it's a great lens and very sharp.

i think the best lens for night photography is canon 17-40 f/4 L .. it's razor sharp, light and enough for wide range..

or you can think EF-S canon 10-22.. it's awesome for 1.6x CMOS devices

Cannon 50mm f1.8

I have this lens for a while and it great in low light and for portrait too...It cheap...But bare in mind it is a fixed lens...and be careful when you using it at low f-stop, I have experience of pictures being out of focus..may be because i just dont get use to the lens yet...

Canon low-light lenses:

EF 50mm f1.2L USM

EF 85mm f1.2L II USM

EF 16-35mm f2.8L II USM