Over my years I have come to to conclusion that I don't like to carry weight on my back if I can help it. Some bikes I ride don't have racks so I will. And I will use a camel bak for hydration on long mountain bike rides in remote areas.

So I have every option, 2 backpacks, several messenger bags, and an Arkel commuter pannier. and I've used them all extensively for commuting. BUT, my favorite by far is the Carradice Nelson Longflap saddle bag with a Bagman support rack. It's old school and it's amazing. I've hacked a quick release mounting system on it and a shoulder strap for carrying it off the bike. Holds my clothes, lunch, laptop and extra bits. Great for touring or long gravel rides too. The weight is perfectly distributed and you don't even know it's there.