That's a great and very practical question! For most standard urban trash cans—the kind you'd use in a kitchen, bathroom, or office—the best liner is a standard-duty or heavy-duty drawstring trash bag that matches your bin's gallon capacity.
The key is fit. Check your trash can's volume (usually 13-gallon for a standard kitchen bin) and buy bags labeled for that size. A properly fitted bag will tuck neatly over the rim without excessive overhang or slipping down inside. Drawstrings are a favorite because they make tying and lifting clean and easy.
For durability, look for leak-resistant claims and a thickness of 0.9 mil or higher for everyday use. If you dispose of sharper items or heavier waste, consider a 1.2+ mil "heavy-duty" bag. While specialty liners like scented or compostable bags exist, a reliable, unscented polyethylene plastic bag offers the best balance of cost, strength, and availability for daily urban living.
Ultimately, the "best" liner is one that fits snugly, resists tears and leaks, and simplifies your trash removal routine. Stick with a trusted brand's standard lineup for consistent performance.