Sndr . , Aug 07, 2006; 12:26 a.m.
You can do the math: for every extra stop in aperture, you can halve the exposure time. Once the exposure time is less than about 1.5 times the focal length (for your DSLR) the effects of camera shake will probably be small enough.
In truth, however, it's unlikely that you will be able to shorten exposures enough with a lens and high iso for picture quality to become acceptable -- to you.
As for good lenses for night photography: the biggest optical problem in night photography is usually lens flare (because of the high contrast of lights vs. a dark background). The best lenses to deal with that are the simples ones, with the lowest number of elements. That means primes, preferably normal lenses (50mm), and usually not the fastest lenses. And don't use UV filters: their two parallel air-glass interfaces are just perfect for introducing ghosting and unusual flare.