Thought I'd add my own two cents.

Breeds: Yep, only one breed, many varieties. Only the hairless needs a little extra consideration. Hairless and haired can be housed together. You'll be more concerned about males or females. Males get bigger and CAN be more calm (not always). Try not to be a hater of white rats if you post on any rat forums, you could be hurting feelings of others. Whites tend to be the first to go as feeders because people consider them boring. Besides, himalayans are born white and don't change for 8-12 weeks. The next white rat you see could be a himalayan baby.

Housing: People will argue to the death over aquariums. They are used for mother rats with small babies without harming the rats. Also, lab rats are kept in plastic tubs with only top ventilation. There isn't much real evidence that a properly kept aquarium is harmful. But its not ideal.
A wire cage should have 1/2" mesh, not 1". Shelves should be covered somehow so they aren't always walking on wire.

Litter: Kiln-dried pine can be ok if you use pine from a company that dries it properly. Phenols are believed beneficial to mammals, other hydrocarbons in the pine are harmful when not removed. I prefer to buy cheap fabric and make squares big enough for the cage floor. If you make 7 of them you can change them daily and wash at the end of the week. Smaller pieces of fabric serve as beds. Much cheaper in the long run then bedding.

Food: There are few foods rats can't have. I really don't like feeding anything with soy to my animals, especially rats. Do your research and see what food you find acceptable. Trying to push nutritional info on people would be like trying to get all dog owners to stop feeding kibble. I don't like harlan teklad, but its probably one of the best lab blocks made.

Other: Rats are expensive when they need vet care for respiratory infections. There are some things you learn as you go. For instance, I give my rats alcohol-free echinecia tea in their water bottles one day every two weeks to help with their immune system.
Boy rats like the wheel about as often as girl rats do. Don't exclude a great toy because people tell you their boys are too laxy for the wheel.
Quarentine new rats away from other rodents.