It all depends on what kind of car you are running and how much you want out of it. As a general rule, higher lift can mean changing to a taller valve spring, which may mean machining the spring seats down a standard amount, usually .100 thosandths. If you want to avoid this, you can usually go up to maybe .475 lift without running into spring bind or crashing the valves on the pistons. You CAN monkey with the duration, opening rate, and lobe separation to see significant performance gains. I recently built a '64 El Camino with a 327. I have a set of pristine '65 1.94 Fuelie (Camel Hump) heads and wasn't about to machine the spring seats from the stock configuration. So I ran a Crower Compu-Pro cam and lifters, 286 dur. intake, 290 exhaust, .470 lift and 112 degree lobe. I wasn't too keen on 112 degrees below 300 duration, but the cam really makes a lot of power all across the RPM range and it pulls hard to over 5000. A great street cam, and it has a nice (although slightly subdued) lope at idle.
Good luck and good hunting.