Here's the deal kids...
Unless your whites... socks, undies, etc.. are dingy, they'll go in with the colors just fine. If they are dingy, and every once in a while for good measure, wash them by themselves with half a cup of bleach to brighten them up.
As for darks and reds, wash them by themselves the first go round or two when they are new, or that nice new red shirt might just make your socks pink. After they've bled though, throw 'em in with everything else. Cold water is fine btw, no need to heat it up, the detergent will work regardless, just may work a bit better if the water is hot, but not enough for you guys to worry about it.
If anything is stained, say with spaghetti sauce or some such thing, pre-treat it with some stain remover, or just rub a bit of detergent directly into the stain before you drop in in with the rest of the load. If the stain is on something white, use a bleach pen on it, those things are awesome.