Yesterday marked the start of Canon's rebate season in the US and this time there's no forms to fill in, the discount is applied at payment.
Between May 18 and July 19 Canon are offering the following discounts:

Body / Lens / Flash	Cashback
EOS 5D	$300
EOS 40D	$200
EF 70-200mm f/2.8L IS USM	$125
EF 85mm f/1.2L II USM	$125
EF 16-35mm f/2.8L II USM	$100
EF 100-400mm f/4.5-5.6L IS USM	$100
EF 50mm f/1.2L USM	$100
EF 35mm f/1.4L USM	$100
EF 70-200mm f/4L IS USM	$75
EF-S 17-55mm f/2.8 IS USM	$70
EF 17-40mm f/4L USM	$50
EF 70-200mm f/4L USM	$40
EF 100mm f/2.8 Macro USM	$35
EF-S 60mm f/2.8 Macro USM	$30
EF 28-90mm f/4-5.6 III	$15
Speedlite 580EX II	$30
Speedlite 430EX	$15

Click here to get the coupons

For European readers, a slightly different set of rebates have been going since March and finish 30th June so get in quick!