You would not be able to control the 580 on camera. Which, in turn would mean you would need two recievers.
The 580EX2 has a PC sync jack, so just order the CSRB and use the included PC sync cable.
The 430EX2 has no sync jack, so you either have to modify ($5 worth of parts and an hour or so of time), or purchase the AlienBees Speedlight Foot Adapter ($15).
I modified my 430EX2, it's quite simple, but you void the warranty and will end up breaking a small piece of plastic that's really unnecessary.
However, if you're using just speedlights, it'd be much more logical to go with something like the Yongnuo RF602's or Cactus V5's. Both act as Transmitters and receivers. And they have a hot shoe, so you can fire your 580 on camera using them.