Originally Posted by kunik 
For the price and size the 24-70 is surprisingly unsharp. I didn't realize that until recently but having seen several examples it appears to be consistently true. That is why I went with 24-105 for my Canon system. I agree with you that if you're not going to match "L" glass to the mkII you bought into the wrong system.
The only flash that Canon makes that can be used as wireless commander is the 580. The EX designation would appear to indicate that the new flash can be fired remotely from a 580 but I would be shocked if it could operate as a commander
Right...the 580EX or EX II are the only Canon branded flashes which will function as a 'master' and control other slave flashes. One needs to check the flash intended as a slave to see if it will operate in that mode or not. Best option is a 580EX II and a 430EX II if one wants two flashes.
One caveat is the control is not RF but only IR so there are some potential limitations in the remote ability. That is where the whole Pocket Wizard and like devices come into play and then things get costly quickly at around $200/flash just to get it off camera wirelessly with remote config control for each flash as well as, or via, the master. I opted for some generic 'ghetto triggers' from eBay that work fine for my basic needs...not perfect but then again < $50 including shipping to fire up to four flashes off camera....but no ETTL/ETTL-II control, all the flashes must be set manually.