Going to a LCS (Local Card Store) will generally see the least amount of money as they will offer pennies on the dollar as they want to resell for a profit.

Another option might be to try and sell on places like Craigslist.  You would likely see a higher return, but Craigslist has its pitfalls (i.e. security, etc).

You can list the cards for sale on NonSportRealm.com and see if there are any takers.  We have a "Wheeling and Dealing" forum where you can post, or just add the cards to your sell list.  This is essentially like dealing with Craigslist except it is remote.

The "last" option would be to put the cards on eBay.  Selling higher value cards outside of a set will generally net more money than lumping them together.  Generally if you sell cards in a set you will earn less than selling them individually, however, the time and effort to sell goes way up.