Favorite low light walk around lens for 7D?

I am interested in nighttime street photography and want to get a 7D (FF is out of my budget, plus a little big). I've been looking at some of the fast primes available (24mm, 35mm) and was curious what your favorite low light lens is.

I don't really like carrying around more than one lens but would consider carrying two if there is a recommended combo.

Would you be happy walking around solely with a 35mm f1.4L?

Whats your standard low light lens?

Thanks!