In reply to peteclark:
If you can; it is worth waiting
Lots of new DSLRs about to be launched around October so current favourites may soon be out of date, but also on offer for sale prices.
Of course the Canon 5d is impressive, it bloody well should be at £2,000 for the body alone. Don't expect canon's cheaper bodys to be the same.
This is an important decision as it will be expensive to change brands once you have some extra lenses. I would recommend some time in a friendly camera shop comparing Canon, Pentax and Nikon cameras - ideally mid week when the staff will have more time. How they feel is as important as features. Obviously weight and toughness can also be important for use in the mountains.
Everyone will champion their own choice, and for what it's worth Pentax is my recommendation. They are making a come back with major investment (new lens factory) with new cameras across the amateur to pro range and loads of new prime and zoom lenses. Latest bodies have antishake built into the camera, not the lenses as with Canon and Nikon - so is less costly.
The new K10D will be out soon and it looks like it will be the dog's bollocks
http://www.dpreview.com/articles/pentaxk10d/
If you wait can wait until Oct Nov there will be plenty of independent reviews on the K10D and also latest Canons, Nikon etc.