Dan, I got engaged on Lake Manatoba - something like that - in the mountains towards Queenstown in NZ. Beautiful area. Shame the marriage didn't last, but nice place to be engaged.
My favourite place is the photo I use here as part of my name - it's a small reef off jersey.
However, if were talking further a field, my favourite holidays were the fly drive ones we had around western America, the Rockies and the big national parks. Wonderful.