
Hi, I am a surf photographer who normally hides far from the subject behind a 600mm lens (I started 3 years ago from scratch but am learning fast!). I have though on the odd occasion taken family portraits on the beach for which I used an EF-S17-85mm IS lens on my 20D body.
I have recently upgraded to a 1D MkIII (

) and the 17-85 lens will not fit the body so I need a replacement. Whilst the purist will frown at my use of a zoom lens I find this helpful for these shots as I follow the family around the beach as they play and pose and I don't often have time to position my self to catch a particular moment.
It would be great if I could have suggestions as to a money is no object Canon solution and also if there is a Sigma/Tamron solution that I could also consider that will give good results.
Oh I forgot to mention

- I would also like to start taking land/seascape photos to sell as postcards and prints, would I be able to use the same lens as above? I would also like to photograph my wife's paintings to reproduce on cards (up to 1m x 1m) would the 50mm F1.8 budget lens be the best bet for this (the 17-85mm lens tends to distort the frames).
Sorry if this is a bit of a big subject, but I look forward to any help/suggestions/input.