For my night-time photography I usually shoot with a Canon EOS 7D. I use one of two lenses. My traditional one is a Tokina 11-16mm f2.8. It's not a super sharp lens, but it's versatile. My more recent acquisition is a Rokinon 14mm f2.8 which has a good reputation for night-time photography. Its minor downside is that it's manual focus only and manual aperture only. However, for nigh-time photography, this doesn't matter.
Whichever lens I use, unless I want to capture star trails, I set the aperture as wide as possible (f2.8). I set the ISO settings to 1600. You can push it further, but at the cost of some additional noise. For pictures of the Milky Way I keep my exposure between 8 and 60s. Over 10s and the stars start to blur.
To capture star trails I lower the ISO settings to 400 and increase the exposure to 4-6min.
I focus manually using the Live View mode, zoomed in on a bright star.
Of course, the conditions have to be right. Ideally, a clear sky and a new moon. These past few days the moon is gibbous, and I have to wait for it to set, at very inconvenient times (3am-5am). It also pays to wait for a good location of the Milky Way. Unfortunately this week the galactic core is not visible when the moon is set, so I make do with what Nature is giving me. I hardly complain :)