If you do file a domain name registration dispute with ICANN, be absolutely certain your claim is ironclad. Also keep in mind that this will (last I looked) cost you around $1500, which is often way more than the person who owns the domain would ask to sell it to you.
If you do intend to file a dispute, see if you can get the person who currently has the domain to make an offer to sell it to you first. This generally helps prove bad faith if they're also not using it (it's parked or something).
If it expires in a few years, don't even think about messing with the domain backordering services. Their function is to register the domain for you faster than the other domain backordering services, and/or the type-in public. They're generally a waste of time to begin with, since they can only help you after both the registrant and the current registrar have allowed the name to drop. If it's a good name, many registrars these days don't allow the name to drop to the public level at all, instead keeping it and putting it on auction.
Also, if you haven't already, stop going and visiting the domain name in your browser. Any kind of typin traffic increases the value of the domain name significantly. If your customers are also typing in the domain, do your best to get them to type your current one properly. If you can lower the amount of traffic to the domain before you make an offer, you'll almost certainly get a better deal.
If you do plan to make an offer, try checking to see what other domains the owner has, and start by inquiring about some other one. When they quote you a really high price, act uninterested, and inquire about several others, including the actual one you want. As others have said, avoid any association with your real domain.
If you do get in touch with the owner, and they're willing to sell, usually they'll quote some astronomical starting figure (often 5-10k for middling-bad domains). This is fine, offer them a lot less. A good rule of thumb is to aim for a final selling price of 10% of the initial request.