I've got a Deuter Futura 32 (You can get smaller sizes as well). Really well made, well organized, great thing is a divider in the main compartment, integrated rain cover and has a zipped pocket on the hip belt. Good harness and the air flow back works very well. Vaude bags look good but also have a look at Osprey. I had a Osprey Kestrel. A bit heavier due to materials used but also good harness, good ventilation etc. Great customer service from Osprey UK as well.
Have a look on Wiggle. Innov8 are doing some good looking 25L and bigger packs, they look very smart, saw a guy with one, not too wide on the back, pockets on the hip belt (they are very useful).
Amazon has various Karrimor rucksacks on sale now. Might not be a posh brand but higher models seems to be well made and have good features and the air flow ventilation similar to Deuter.
If You are not after a top loader rucksack I always like the way Deuter Trans Alpine look. Loads of pockets, usual Deuter quality. My mate still has a very old Deuter pack that is perfectly usable.