Since your question is not really clear here’s my thoughts.

I use two slave flash units that came from Ritz Camera.

These are external flash units that trigger from your main flash either your on board or an add on flash unit. They detect the flash from your camera and go at the same time. You can get them out as “out riggers” and they’ll supply lots of extra light for big shots.

When you say “flash setup”, what exactly do you mean?

Are you looking for a three or four head studio flash system with a wireless triggering system?

Are you looking for a hand full of external flash units that can be remotely triggered using the on-board flash unit with stands, light shaping and conditioning devices for use on remote locations?

Here is a link to the external flash systems Canon sells.

Using the ST-E2 speed light transmitter, you can wirelessly trigger any of the Canon flash units

Link to all the studio flash units you could ever imagine.

You will need a wireless controller to set off the flash. Popular options are Pocket Wizards and Radio Poppers. You’ll need one for the camera and one for the flash.