there's a rebate program going on with canon equipment. check b+h and amazon for lowest prices.
personally i'd go with the 24-70 since that's pretty much the ONLY lens I use. it's generally the most used focal length and IMO the best all around general purpose lens. it's relatively knew (only a year old) so I don't think prices will go down lower than they are now. if you need it, get it. no use with time waisted waiting for the price to go to its lowest pice. if you're desperate for a cheaper price go buy used.
a LOT of people would suggest the 24-105 f/4 IS, which is another great lens, though I'd much rather go for the larger aperture. the only advantage of the lens would be for video. if you'll be shooting video than the IS is a necessity, but that depends on your needs.
congrats on the purchase!