A sad day: Let's talk lenses!

Today I had to say goodbye to the Nikon 17-55mm 2.8 that I rented. I must say that I loved shooting with it and hope to one day buy it. Do any of you out there own this lens? I would love to hear your opinions on it or any other great lenses. I just own the lens that came with my Nikon D70s. I am looking to purchase a better quality all purpose lens.

For you cannon owners, what is your favorite lens?

Love to hear your thoughts!