best wireless trigger

ok I have the 580exII and will be buying 2 more flashes for multi flash setup. Will I need to get a remote for firing the other flashes if I take the mounted 580ex off . ok lets say i buy a slave flash and want to put the master on the side and the slave on the bottom ,in doing so I will need to have a remote mounted on the camera correct? to send the signal to the flashes .
I want to know what brand or unit you use to achieve this .

If you want E-TTL flash and want to have the master flash over 3 ft. away from the camera, the Canon ST-E2. If the main flash (or any flash, regardless of the output) is closer than that, just get an off-camera sync cord for the Canon hot shoe.

what brand for off-camera sync cord? did some reading guess the st-e2 is what I will go with thanks for the info..

You don't need anything if you're using your 7D and have line of sight. Use the built-in wireless. If you're using one of your other dozen or so bodies, then you'll need either the suggested ST-E2 for the E-TTL wireless or you can buy triggers if you're going to be shooting where line of sight isn't practical. You didn't say what you're using it for.