The diaper that is best for infants is Pampers Swaddlers, which are very soft and comfortable as well as Huggies Snug and Dry diapers or even Pampers Baby Dry diapers.
Other good budget diapers for infants are Parents Choice Diapers, Gentle Steps Diapers, Cuties diapers and Luvs diapers.
For toddlers the best diapers that don't leak are the tape style Pampers Cruisers Diapers, Pampers Baby Dry Diapers and even Pampers Swaddlers diapers.
Pampers Cruisers tape on diapers are best for active toddlers that are always running, jumping, playing etc and they have held up really well to my kids active play and heavy wetting.
During the night I would use Pampers Baby Dry diapers on my toddlers and they also worked well.
Before I started using Pampers Cruisers tape on diapers for my toddlers I would use Pampers Baby Dry diapers and they also worked really well.
Huggies Snug and Dry Diapers are also good for babies and toddlers that wet a lot, although they are usually more expensive than the Pampers diapers are.
Luvs are also a good budget diaper that are made by Pampers and I've had some good luck with those, but the Pampers Cruisers and Pampers Baby Dry diapers as well as the Pampers Swaddlers diapers are great.