3x 600EX-RT = $1,887
3x 580EX II
2x PocketWizard FlexTT5
1x PocketWizard MiniTT1
Now try to use all 3 off camera. You need one more PW for $200 or another 600EX for ~ $600
I suppose you could get the ST-E3 for another $300.
Your PocketWizard solution would certainly work. With the 600's, I like being able to control the flash group functions from the master/ST-E3. The menu system is easier. And it's pretty nice actually not having to use PocketWizards as an added layer for radio.
For me, the dealbreaker with PocketWizard was with the issue with TT5's frying 580exII units a while back.
Certainly the 600's are not for everyone, but I certainly am enjoying them. It was definitely a nice trade-up from my 580exII's.
There was some language in the manual for the ST-E3 that led me to believe that there will be other (even third-party) products coming soon that will tie-in to Canon's remote system. Who knows - maybe Canon will be making triggers themselves?