Case/Backpack for 40D+Grip & 3-4 lenses + flash (Crumpler/Kata/Lowepro?)

[wicker_man]

I am currently looking for a nice case/backpack for my 40D, as my current Lowepro Rezo 160AW shoulder bag is far too small!

I am considering a backpack style would be more comfortable for carrying my equipment around all day, and ideally something with a laptop section for when I have a photography society meeting after a day of lectures at uni so I can either have my 15" MacBook Pro or lecture notes in the section.

Equipment:
Canon EOS 40D + BG-E2 battery grip, with Sigma 18-50mm f2.8 (usually attached to camera) dims = 14.5w x 16h x 17d (in cm, approx)
Tamron 55-200mm (11 x 8cm)
Canon 50mm f1.8 II (7 x 6.5cm)
Hoping to get a Sigma 10-22mm and a Speedlite flash in the near future.

I have had a look online and seem to like Crumpler bags, and have seen the Farmer's Double. Does anybody have it, and can it hold the above equipment in the photo section?

Others I am considering are the Kata DR-467 and Lowepro Fastpack 250. Or, are there any other suggestions?

Budget wise, I am quite flexible, but would prefer something around £40-50ish, and don't mind a second hand bag (I've already spent a lot on my camera equipment, so I need to make savings!)

I've checked my local Jessops and LCE, but they are small stores with a limited range of bags.

Thanks in advance for any advice.

 

[wicker_man]

Does anybody have any suggestions or opinions?

I quite like the fact that the Lowepro Fastpack 250 has a side access door, so the whole bag doesn't need to be removed to get a camera out. Are there any other bags which have such a feature?

 

[Euan]

the kata 3n1's have that feature as well (side access), ive got the 3n1 20 and it should hold everything your after but i think its a bit over your budget new.