Hi. If you want a really great nav bag and are prepared to pay for it, give Tumi a try.
Tumi are expensive (don't go for the leather option) but I have had one for two years and it's been fantastic. Great range etc. They are business type briefcases and luggage with ergonomic designs and are very durable.
Have been voted world's best luggage before (e.g. Robb report).