Andy, I was having the same dilema as you around about September last year. I had been using a 16mp Samsung compact (ST66) and it had served me well, (and still does) but I knew that I had reached the point with my photography where I needed something that could perform better than a compact.
Having used SLR cameras before I knew that they could be cumbersome to use when hillwalking, also add to that the bother of carrying and switching between two types of lenses, made it an option I was reluctant to take.
Everyone it seems is raving about the lighter but equally expensive mirrorless models e.g. the Sony RX100 III and the Fujifilm X1-T. T Although they are light, they still require a variety of lenses. Their biggest drawback for me was the conditions I'd be shooting in, and Sony especially don't like it when it's only "spitting".
The majority of bridge cameras available didn't satisfy my tick list either. Big zooms, huge megapixels but poor sensors, no RAW file capability and no resistance to inclement weather had me in a catch 22 with every conceivable camera option.
Then I found something which pretty much covered everything in my wishlist...
...The Fujifilm Finepix S1. Here's the spec below.
http://www.fujifilm.com/news/n140106_03.htmlIt's like a nice small DSLR that can shoot in both RAW and Jpeg formats, with an attached x50 zoom lens. (which unlike other superzooms, does actually deliver good results when fully extended.) I don't need to carry an extra lense and the weatherproofing is working well.
Here are a few images from mine to show it's image quality...
Low light
Grey sky day
Zoomed in x50
What it looked like zoomed out
At the end of the day, you will know best about what features and functions are most important to you. Everyone will come on the thread and tell you that they chose a great camera, in much the same way as if you asked what waterproof jacket should I buy, you'll get 100 different answers.
The Fujifilm Finepix S1 ticked all my boxes and didn't break the bank, (by much).