Leather is a classic for a reason. Natural leather just gets better-looking over time if you don't mistreat it. Scuffs on it become noble patina instead of signs of wear. It'll easily last five to seven years minimum if you don't beat it up. The downsides are weight and price, plus you need to maintain it occasionally. But if it's an everyday bag for a couple years, it'll pay for itself.
If leather seems too expensive or pretentious, then modern polyester or nylon is also an option, though there are nuances. Synthetics are lighter, cheaper, and dry quickly, which is convenient. But after a couple of years, nylon can start delaminating at the fold points, the material gets duller and starts to look tired. Quality ripstop or ballistic nylon holds its shape better than regular nylon, but it's still not the same as natural material.
I carry a leather bag myself because I need reliability - there are things inside that can't get wet. But if you get rained on a lot or live somewhere damp, leather will need more attention. Look at your lifestyle: if you want to buy once and not think about it - go leather. If you prefer lightness and don't mind replacing it in a couple of years - quality polyester.