Yeah. I think so too. I would love to have some but I only have one tank and its currently occupied by my baby betta. I don't think he'd appreciate being snapped at by a crayfish. CPOs are known to be as feisty as a betta and eat the occasional fish, snail or shrimp when housed with them.
Okay. Sounds like a plan. Just be aware that they aren't as cheap as, say, a comet goldfish, but not outrageously expensive like some rare and exotic fish. They usually run from between 10 and 20 dollars per individual crayfish, depending on where you get them from.
Hmmm...how about a community tank. You could have a range of tetras, a pleco/shoal of cories and some gouramis. Also, angelfish are fairly popular in community tanks, but make sure you don't keep them with small tetras (e.g neon tetras) as they could eat them!