Does it have to be designer?
Well, yes. We hate to be snobby, but "investment bag" pretty much implies "designer." Of course, there are many, many designers out there, so you don't have to lay out thousands of dollars to get something special. You do want your bag to be stylish and well-made, but don't worry about following the latest fads -- and skip the flashy logos, unless you want your bag to be screaming "2010" several years down the road. Hard-core "bag ladies," with their limited-edition Gucci satchels, might look down their noses at your oh-so-pedestrian Coach purse, but don't worry about them -- if you love it, and it fits your budget, go for it.