Avoid gel insoles.
Apart from that, you really have to listen to your feet and try different things until you find what works for you. Your feet and mine are different feet. Experiment with different types of hiking socks, insoles, etc. until you find the system that gets you down the trail with minimal discomfort. Whatever that system is, that's the best for you.
I use those Dr. Scholl's custom orthotics (the one's with the booth like fitting area in local Walmarts). Those things have REALLY saved my feet and knees. I have a pair now for every hiking and walking shoe I own. When my knees or feet start bothering me again, I replace them (which so far, seems to be about every two years or so). Like Newandertahl stated you'll have to find what works for you, but these do have the ability to give you "customized" insoles for a lot less to see if those will provide sweet feet relief! But good luck in your search.
When you begin to get a blister, or when a part of your shoe is rubbing your skin, moleskin can be your best friend. Purchase it at the drugstore, cut it to size and stick it to the affected area. Moleskin saved my life many a day.
Thanks guys for the advice. I've heard already about those Superfeet insoles but I never tried them. They are not cheap but I think they may be worth the price.