A tote bag is perfect for work days and weekend trips. It will fit all your essentials - exactly what you want from a bag on long days in the city.
If you're budget-restricted, check out this Ted Baker Tote Bag. It's a great product for a good price. Another savvy option is this Marc Jacobs Tote Bag. While the price is rather reasonable, be sure that this product will become a great addition to your wardrobe. You may also want to look at this Tote Bag. This item is not expensive either, but it will make a difference in your wardrobe.
If you want to splurge, then you absolutely must check out this Gucci Tote Bag. This item seems pricey, but it's top quality. Another product we're drooling over is this Givenchy Tote Bag. It's pricey but you get what you pay for. And one more item you might be interested in is this Stella McCartney Tote Bag. 'Cause you deserve nothing but all the finer things!