Sorry that didn't fix it. It did it for me. Now I do caveat that I use an external Bluetooth GPS antenna since the GPS in the Galaxy S is known and acknowledged by Samsung to be weak (one of the few drawbacks to the device). That causes the internal GPS to lose signal occasionally when inside a vehicle. That may also be part of the issue. But I was using that antenna before I found Waze, and I was getting the crashes regardless of internal or external GPS, until I turned off the wireless location. Though they were more regular with the internal GPS.
Oh, one other tip I've seen is do you use the built in mapping software like latitude? I've only id'd that as the cause a couple times but trying to run waze and latitude at the same time has caused a couple crashes. Now this was caused when I'd intentionally opened the other mapping tools, not just when they self load in the background. Not sure what the difference is there just what I've tried.
I'm not really sure what to have those still having problems at this point, just sharing my experiences and observations in hope that something can lead to your full enjoyment of the Waze experience. Oh and one thing, make sure anytime you do crash, when you get back into Waze and it wants to send a report, let it.