I am with Paolo. I love backpacks, and I have used a fair share of them over the years.
I used the Peak Design Everyday Backpack 30 l for quite some time, but it is too sturdy and heavy (~2.1 kg when empty) for me. I found that I like to optimize for weight, so my choice for a long time was a Heimplanet backpack, called the Motion Arc (20 l). I love how it looks and it is probably the most comfortable backpack to carry ever, also because it is very lightweight at just just 740 g. It has gotten a bit too small for my needs and I have had some quality issues with it – the waterproof coating on the inside was coming apart after a couple of years of heavy use – but Heimplanet sent me a replacement for free!
Now, the Tom Bihn Synapse had been on my list to try out for a very long time. I think I had it in my head since I read a blog post many years ago, where the author used it as their one-bag travel bag. Last year I finally pulled the trigger on a Synic 30, which is kind of the improved successor of the Synapse. The price – and especially the shipping to Germany – are quite outrageous, and the main reason I didn’t get it sooner. But I am glad I bought it, because I like it a lot. It is not the prettiest bag, but it is very well made, very versatile and the organization is exactly what I need.
What I don’t need, is anything special for my camera. I usually just dump it in the main compartment with the rest of my stuff. When I am carrying more gear, I use a pouch made by Crumpler, which I bought for very cheap at a photography trade show. I find it more versatile than having a dedicated photography backpack, that is only really useful for camera gear. Also, when travelling I can just pull out the pouch and leave it at the accommodation.
With the Synic I like that for my daily carry, I still have enough room to do some light grocery shopping and it fits most handicrafts the kids make in kindergarten.
Even though it is not perfect (eg. no waterproofing) I am planing on using the Synic for a very, very long time and (for now) I am successfully resisting the urge to watch any backpack reviews, whenever I come across them on YouTube.