I have, for sale, a Canon 85mm f/1.8 lens in excellent condition. It's a little short for most plane-spotting, but it is an excellent portrait lens, performs well in low light, and focuses fast enough for sports photography. I bought it a couple of months ago to fill in the 70-100 gap when I realized that my telephoto lens of choice would start at 100mm rather than 70mm. But my financial circumstances have changed a bit and it's delaying the purchase of said telephoto lens that I would use much more.

The Digital Picture's review:
http://www.the-digital-picture.com/Revi ... eview.aspx

A few of shots I took with it:
http://www.flickr.com/photos/adamtrilling/2609061165/ (this is a multiple-exposure shot, so no EXIF data)

This lens retails for $350...I'm asking $310. PM me if you're interested.