Just a note on the Thermos Ultimate.
I have been seriously impressed with this flask. I don't take it into the hills much but I do take it on winter kayak trips, have it in the car for after a day walk, fill it with mulled wine for an evenings punting on the Cam etc...
It's main use though is brewing my tea at work (T2 New York Breakfast, if you are interested)
I just opened a flaskfull that I made at 2pm on Friday and then forgot about.
46 hours later I have drunk it at a perfect temperature (imho) of 57°c.
For the type of tea I make, the flask does not 'stew' the tea either. It only seems to start to oxidise once it has been opened.