First, I'm really happy to see a onebag offshoot community happen here outside of Reddit!
Figured we should get this community going by posting what our go-to bags are. Why did you choose that bag? What do you like about it? Anything that could be improved? Any other bags you're eyeing?
My current go-to bag is the Osprey Fairview 40. It's incredibly comfortable and suits my body (I'm very petite) better than my previous bag, which was the RedOxx Sky Train. For me, the issue with the Sky Train was the lack of hip belt for heavier loads, especially when it was packed full (38L capacity). I also wasn't too happy with the organization of the Sky Train either, I think I much prefer having one single compartment and relying on packing cubes.
I was so surprised how comfortable the Fairview was when fully loaded. It didn't feel heavy at all. I guess that's the benefit to having a pack that fits your torso length, along with a proper hip belt!
I'm not a full on one-bagger as I tend to have a bag and a personal item. I still love my Timbuktu Co-Pilot small - fits on every flight except occasionally Icelandair and those skateboard wheels have been fine on everything but loose sand.
I currently alternate between a Fjällräven Ulvö hippack large/4l (I'd like to try a medium) and an Ikea Värld 16l depending on if I need to carry a laptop.