The Canon L lenses are pretty cool. This (and the whole set of tour action photos for that matter) were taken with a 300 F4L that I hired for the tour:
If you want a go with a pro lens, Lensesforhire.co.uk do really good rates. I had the 300 F4L as it was light and I knew the light would be good, for 2 weeks for about £100. That was well worth it as far as I was concerned!
For the interested parties, taken on a Canon 40D using machine gun mode (6.8 fps), ISO 100 at F4, 1/1250. Wanted to capture action and get shallow depth of field. Had I closed it down a bit the image would probably have been slightly sharper, but at the cost of motion freeze. Worked pretty well though.