Kenji, over at the Serious Eats blog, has done some experimenting with sous vide (pre or post bath sear?, aromatics, etc.) and posted lots of photos and data.
Re steak temp, he says this:
130°F (medium-rare): The meat has begun to turn pink, and is significantly firmer. Moisture loss is still minimal, at around 4%. Intramuscular fat has begun to render, which not only lubricates the meat, making it taste juicier and more tender, but it also delivers fat-soluble flavor compounds to the tongue and palate—beef at this temperature tastes significantly "beefier" than beef at 120°F. When tasted blind, even self-proclaimed rare meat lovers preferred this one, making it the most popular selection.
Below is the link to the steak article. Just search the site for sous vide for others.
He also tells how to make a homemade rig with an ice-chest.
http://www.seriouseats.com/2010/03/how-to-sous-vide-steak.html