What's native in your state -
http://iz.carnegiemnh.org/crayfish/country_pages/state_pages/michigan.htm
Cambarus diogenes - You're not likely to run across these as they are decreasing in number in most places, and require specialized traps since they're a burrowing species and not actively found in water systems. They require specialized set-ups to thrive, as well.
Cambarus robustus - One of the larger cambarus species, not too fancy in appearance or coloration. Easy to maintain in most set-ups.
Fallicambarus fodiens - Really nice crayfish, little bit harder to find. But they generally have nice coloration and/or patterning. Easy to maintain in most set-ups.
Orconectes immunis - A small, rather plain crayfish. Very aggressive, but easy to maintain under almost all conditions.
Orconectes propinquus - Very cool crayfish in my opinion, just because they tend to have a much darker coloration than most crayfish. Again, easy to maintain.
Orconectes rusticus - A very large, aggressive species. Invasive in most states, if you catch these don't release them anywhere. But very easy to keep, breed, etc.
Orconectes virilis - Another one of my favorite species. These guys sport huge bumpy claws, are pretty docile and tend to change colors in home aquaria from what they were when they were caught. Very easy to keep, keep the water cooler with these guys and don't try to breed them (it's not possible in home aquariums).
Procambarus acutus acutus - This is a typical bait crayfish that's available at most bait shops. Very easy to keep and breed, and can come in a variety of colors and patterns.
In LFS, it'll vary upon the area and the store. But you'll probably run across the Electric Blue Crayfish (Procambarus alleni), which is easy to keep and breed but highly aggressive. Red Swamp/Radioactive Orange/Ghost White Crayfish (Procambarus clarkii), which is easy to keep and breed, moderately aggressive and often found in bright red, orange and pure white (and as feeders in their normal rusty coloration).
I have photos of a lot of these crayfish in my albums if you want to run through, and there are plenty up in the sticky threads.
