So I couldn't resist a smoking deal on a 5DII and finally made the plunge and upgraded from my 20D. I also made the choice to get the 24-105 kit because it was also a really good deal (don't worry, it wasn't from a storefront shop in Brooklyn). Btw, in case anyone else is interested (this deal was still good last time I checked) you can pick up the 5D from circuitcity.com for $2500 - $375 for 15% bing cashback and/or the kit for $3300 - $500 for 15% bing cashback. I couldn't pass up the kit for $2800 shipped. Anyway, so now I'm figuring out what to do with this lens. My initial inclination was to try and trade this lens (plus some cash) for a new 400 f/5.6 or an even trade for a like new 400. I haven't gotten any bites on craigslist, though, and know that there probably aren't tons of people out there walking around with new 400mm lenses that they want to get rid of (especially for a 24-105). I also called one local shop (I'm in the San Francisco area) who basically told me that what they could offer me wouldn't be worth it for me. Anyone have ideas for other routes? I could keep the lens, but I already have a 24-70 f/2.8 and 70-200 f/4 and I'm not sure I can justify the expense of also having the 24-105 (although I do a lot of photography while backpacking, so I might be able to be convinced otherwise). Am I missing a reason to have the 24-105 on top of what I already have other than the convenience of a lighter lens with a little more length than the 24-70? (In case it matters, I also have the 17-40 and 50 1.4) Should I just sell the lens and then use the money to buy a used/new 400? I was trying to avoid the big cash craigslist transaction and I have never sold anything on ebay, so i'd assume it'd go for below market just because of a lack of history. Thanks for any suggestions!