Use any name brand 10W40 motorcycle oil.
Make sure you are using motorcycle oil and not automotive oil. Motorcycle oil will have additives that are friendly to your clutch. Also, motorcycle oil runs hotter than automotive oil. Motorcycle oil will have additives that will better deal with heat.
Motorcycle oil will cost you more than automotive oil. However you will usually find it for less at most major automotive parts stores.
I also have a tip on selecting your oil filter. Use a Wix oil filter. It is far superior to the cheap made in China filter that the Honda dealer will sell you and will cost you a few dollars less. Any automotive parts store that sells Wix filters will either have them in stock or can special order one. A special order filter usually only takes a day or so to get. You didn't state the engine size but Wix part number 51334 should work. It fits Honda Shadow 500, 750, 800, and 1100.
