There are some good suggestions on here, and i went through the same debate for my 2012 hike.
First off, the cannon, Olympus, Nikon, and pentax are all great cameras on the trail.
I debated over these, but ended up taking the Fujitsu xps20. What made up my mind was price.
I decided carrying one of the more expensive cameras on the trail was not a hassle i wanted. The xps20 cost me right at $120, is 14mp, waterproof, shock, dust proof, and took great pics. I just carried it in my hip pocket of my pack, and was never worried about breaking it. It took good underwater photos too.
Just saying, figure out what works for you, and what your comfortable carrying, because honestly all the name brand waterproof cameras are great for the trail.
The gopro is great too for doing timelapse, and it has a lot of attachments to attach it to your poles, chest, or helmet.
A camera that works for one hiker, isn't always the best for another. Decide what is most important to you.