Another Flash Question

I'm thinking about buy a flash for by D Rebel. I have no expeirence using a flash other than the built in one on my camera. I want to stick with flash dedicated to my camera, and one that will be dedicated to an upgrade sometime down the road. Not any time soon, but someday. I have been thinking about one of Canons ring lites, or the twin macro lite because I want to try some macro shots. On the other hand, I like the Canon 550EX and 580EX because they are much more powerful, and I'm guessing they would be better suited for portraits. I would also consider an aftermarket flash so my options are pretty wide open. I guess what I'm looking for is a starting point. Since I know very little about flash, I don't even really know what to look for. So where do I start?

Get the best factory unit that you can afford for the first strobe. I'd also go for one of the off camera sync cords and some type of flash bracket to keep the unit at least 10 inches above the camera to reduce red eye.

A pitfall to avoid...... My setup: 2 older white-lightning mono's, 550EX and 420EX flash. Objective: To use WL's as main and fill and use the 550EX as the IR Trigger for the mono's and trigger the 420 as a backdrop light.

The WL mono's are older as stated and have a trigger voltage too high for my Canon 10D, so I mount my 550EX via a flash bracket to the hot shoe and set it to Master. I set the 420 next to the backdrop and set it to slave. I place the 550 in "M" Manual mode and power it all the way down to 1/128th power and point straight up. Goal is to activate mono's and trigger the 420. Unfortuneately even in manual mode the Canon flashes send out a pre-flash for metering exposure. There is absolutely no way around this--the flash is not truly manual at all!!!! Very frustrating when used in conjunction w/other studio lights!!!! I personally would consider a NON-ETTL flash if I was buying again.