Usually this is not the best way to find a good knife. Knives that hold their edge a long time usually consist of very hard, wear resistant steels. Look for knives that use ZDP189, HAP40, M390 etc.
Something like this would hold an edge better than most: http://www.chefknivestogo.com/suzddagy24.html
A better way to get a really good knife for you would be to answer the questions at the top of this forum section and then we could choose something that will hold an edge long and would fit your needs and use habits.