I thought Jon Doran's article "Beginners' Basics - Summer Packing" (http://www.outdoorsmagic.com/localiser/member.asp?SP=&v=1&memNo=16) was useful but maybe a bit 'academic'?
3 litres of water might be ideal, but it's also heavy (3kg, Sherlock . For your average 4 hour plod (beginers stuff), surely a litre of water in a squash bottle and a flask of coffee between two is more than realistic?
For an average day out, I'd suggest: Wear a decent base layer, a light fleece and tracksuit bottoms a lightweight waterproof (there's plenty for £50 from top brands) A map/compass (if you can use one) A space blanket A litre of water (an old squash bottle is fine - just top it up in streams) A flask of coffee A sandwich and a few jaffa cakes A handful of jelly babies, and maybe fruit/nuts Lightweight gloves (liner ones are fine in summer) A whistle A couple of band aids
interesting to hear about the problem with the lids corroding - i bought a pack of three in the summer when Blacks were selling them off for £2, thinking that they would be ideal to chuck in the car/'saxk-lid etc and forget. They do come with a lightweight stiff-foil windsield though ehich i reckon i can use with my trangia burner as a lightweight alternative...
I ordered one through ebay a just over a week ago and it arrived this week (Foretrex 201).
Now on the face of it, it seemed like a pretty good deal - about £85 including postage, BUT the package was opened at customs (and an £18 import duty imposed) AND because the power supply is US it cost me a further £20 for a 240 110 v convertor (the 201 is rechargable) - total price about £120, which frankly is the same price as I could have bought a UK sourced one online (e.g. at www.gps4less.co.uk).