Thanks. I just finished my basement and kept asking questions of the electrician to make my plan. I had a dedicated line run to my pinball wall so only my pins are plugged into that circuit that way I know I have 20A available. Even so, when I have friends over, I plug one pin into an extension cord to the receptacle across the room. I would hate to have someone's high score nullified by a brown out.
You should be able to look at the box and easily find out what you are running. On the arm of the breaker or the top of the fuse should be a number, 15, 20, 30 etc... That is how many amps the breaker/fuse and wires can handle.
Do you have 110v receptacles in your garage? 220v circuit is usually two 110v combined so those two 20A lines to your garage could be just for the 220V compressor but might be running off the kitchen's circuit.
You might be able to have more lines run to your house. Most modern houses have 200A service. Not sure how much it would cost but that is something I would seriously look into. I couldn't live off of 100A, too many electronics.
Color preference is up to you. I like my rooms brighter (I'm afraid of the Bogey Man ) so I would probably go with blue but not all people do.