Canon End-of-Summer Rebate (20080831~20081013)

With the release of the 50D specs, Canon needs to clear out its current 40D stock. If you purchase a 40D + EF70-300mm f/4~5.6 IS USM now, you receive an $150 "instant" rebate. The 40D + EF 28-135mm f/3.5-5.6 IS USM Kit lens combination currently goes for $1,145.00 on Amazon.com. Admittedly, the instant rebate isn't that great considering the price of the EF70-300mm f/4~5.6 IS USM ($541.47). You might do alot better just getting the kit and then hawking the EF 28-135mm f/3.5-5.6 IS USM on Ebay for ~ $305 or so (which should draw plenty of bids). Then you'll have a nice, sturdy 40D body for only $840 out of pocket.

If you purchase the newer Rebel XSi + EF75-300mm f/4-5.6 III, you get a $100 instant rebate. Right now the Rebel XSi + EF-S 18-55mm f/3.5-5.6 IS Lens goes for $699.98 on Amazon, which I think is actually a better deal than the 40D (DPreviews actually calls it a "mini 5D;" and it has a few features that the older 40D doesn't, such as contrast-detect live view). The EF-S 18-55mm f/3.5-5.6 IS Lens is very nice, but you could sell it if you already have good glass on Ebay for ~$15 and have the body for $549.98. From what I've read though, this consumer IS len quite nice and magnificently flare-resistant, so you might just want to keep it for the little extra that you pay for it.

Canon usually has another rebate program around Christmas time. I think the previous rebate program before this one--which involved a Pixma printer--was actually the best. I purchased an EOS kit, got the rebates for the printer and the kit, then sold the printer, drastically bringing down my out-of-pocket prices for the EOS body and kit lense.