It appears that Scott and I have the exact same inventory of photo stuff. I have found that the camera body is an inexpensive accessory to the lens.

It seems the 17-55 2.8 is the number 1 "normal zoom" followed by the 15-85. I have both and find I never use the 15-85.

Moving into the tele zoom, the 70-300 is pretty sharp, the trade up/off is to the 70-200 f4, and if you can stretch it the 70-200 f2.8.

I have found that the 17-55, 70-200 2.8 and a set of extension tubes has not left me wanting for anything else. Every once in awhile I long for some super tele but that is pretty darn rare as in perhaps once. The 50 1.8 doesn't see3 much time on the camera

I haven't found the gap of 55-70 an issue, usually a couple of strides forward w/ the 55.

bottom line, get the best glass you can painfully afford - the sensor can only record the light that reaches it. Further, the investment is 90+% recoverable if you take good care of the glass.

I come from the way old school of film, like 1976 and am just flat out amazed at what the cameras can do these days. None the less, if you travel, it is unlikely you will ever be back to that exact same spot with exactly those conditions and the image you capture is literally a lifetime event. One of my first posts was lamenting that I didn't get the better gear and more importantly I didn't take the extra moment to confirm focus and framing and the image is now forever unavailable to me.

The 550 has the same sensor and IQ of the 7d, so captureing great images are possible, might take a micro second longer than w/ the 7d, and the fps is not there, but if you wan't to do video the 550 w/ Magic Lantern runs circles aroudn the 7d so don't accept that you somehow have lesser gear as a reason the image isn't all that it could be.

Happy pix