Still one of my most used lens. Stays on the 7D body most of the time, for sport and wildlife. Often goes in my backpack, and whilst heavy; it's versatile and useable through the seasons - this shot taken in the UK in winter...
http://www.flickr.com/photos/22983840@N08/6405863877/#
Update:
would like to know how people get a flickr image to display and link - I've tried inserting the flickr URL to the "Insert Image" applet, and doesn't seem to work