For your wide angle lens for the 5D, I'd recommend the Canon 16-35 F/2.8L. Its expensive, but its beautiful.. the 17-40 F/4L is very nice too.. but F/4 vs F/2.8... I'd go the 16-35, although it is expensive..
For the flash, The Canon Speedlite 530EX is a great unit.. it lacks some of the features of the 580EX, however unless you're going to use the remote flash capabilities of the 580EX its not worth the price difference I don't think.
I buy all my photography from discount digital photographics..
http://www.d-d-photographics.com.au
They are grey importers as far as I'm aware.. they do however provide warranty.