I would get an '03 or newer with some of the standard warranty still on it. I purchased one with really low mileage and it has been great. Then go to motorcycleservices.com and get an extended warranty for another 3 years. That should cost you less then 1000.00. But, it is well worth it.
Check the service record (buyer should be working with a specific dealer that would have the details as to what has been done). Make sure all the recalls have been done.
Look for one with equipment that you would want on it. Especially consider things like, HIDs and/or running lights, windshield that meets your height needs. I would go with a Custom or better since you will have the sound system with the cd changer.
You may want to consider using
www.nada.com,
www.kbb.com to see values of the model that you are considering and also check out
www.cycletrader.com for available models and pricing. You can also check the BMW Owners of America News in their flea market section for LTs for sale.
Good Luck