I like the added reach of drop bars and regular bars which keep your wrists in a neutral position. It's more comfortable than flat bars. 650b with thick tires would also be good. Ideally a tall stack for better comfort. This would be mostly for sport riding and quick commuting, seems like a cyclocross bike would fit the bill. But they usually don't have enough stack for me.
Something like a kona libre or salsa fargo would fit the bill.