Equipment bag recommendations

I'm looking for a bit of advice / recommendation for a new camera equipment bag.
I currently use a Lowepro SlingShot 200 AW and although I like it's flexibility it is starting to become 'space challenged' and a little uncomfortable when carrying all of my kit on longer walks (8 plus miles).

What would you recommend for a bag that is still reasonably quick to access, high quality build and weather proof (storm proof cover is OK) and more comfortable (i.e. double straps).
I have been considering the Lowepro Vertex 100 AW and the KATA 3N1-20 or 30... any thoughts:

I have the small Kata shoulder bag,(Free with mag subscripion) I find the quality of it very good and light also easy access to kit.
The Kata bag (3N 1 20-30) has been getting good reviews.

I have the Kata R-102 backpack and can recommend it.It can become part of the Kata system. A little pricey though.

I have the lowepro vertex 300aw it's large but superb.I can't beleive how comfortable it is for a bag of its size

I also have the Kata 102 and is very good indeed, is very confortable even with all my gear on it.
Clausio

I have a Lowepro Nature Trekker AW II. In it, you'll find: K10D (soon to be replaced by K-7), K20D, DA 14-f2.8, DA12-24 f4, DA*16-50 f2.8, DA*50-135 f2.8, FA 31 f1.8, FA 43 f1.9, FA77 f1.8, Sigma 70-300 Apo, 2 X Sigma flashes and miscellaneous (filters,...). Not the fastest bag to use, but very comfortable, and weatherproof.

Your gear should be IN the bag, not ON the bag.

I use the Lowepro Mini Trekker AW. One of the big positives are the sliplock pouches which means with the 60-250 strapped to the side I can carry far more than you'd imagine.

I would advise you consider the dimensions if you're looking at air travel. I always take my gear as carry-on.

You might get away with the Micro Trekker, but not sure about the 60-250. Do you use it that much?

Thanks for the replies everyone.

Gareth, yes I tend to carry my 60-250 around almost all the time and yes I would occasionally use the bag when travelling by air. Good points.

Found this deal on Amazon which looks pretty tempting http://www.amazon.co.uk/Lowepro-Vertex-Notebook-Backpack-Digital/dp/B000MUK81E/r...=pd_cp_ce_1 even the one from Amazon directly at £65.83. Only thing is... it's not quick access but I guess you can't have everything

Take a look at Calumet too. They have some nice stuff at good prices. link

If you are intending to fly with it make sure it meets not only size regulations but isn't too heavy in itself. Some bags - the Katas in particular can be ridiculously heavy before you've even put anything into them. Some airlines will weigh your bag, others won't, but if you have to negotiate an aircraft with it and lift it into the overhead lockers you don't want something weighing a ton.
I'm very happy with my Tamrac backpack. Though not fast access it is very comfortable to carry thanks to all the adjustable straps, including a waist strap and chest strap - both increase the comfort when hiking. The tripod holder is on the back of it so it doesn't get unbalanced with a tripod attached. I can fit the Bigma into it easily, either on camera, or more often off camera.
I suggest you find a store with a wide range of bags and actually go and look at them, and see which one suits you best. Take your biggest lens and camera with you to make sure the lens will fit.

Gwyn, good point regarding the weight although for me so long as it is not ridiculously heavy comfort is of the most importance.

In the end I decided to plump for the Lowepro Vertex 100 AW as it looks very robust, gets good reviews and should fit most airline carry on size restrictions. It is a little on the heavy side but I can live with that (hopefully)