I suggest 1 oz of Poorboy's Super Slick and Suds (delicious apple smell). If you prefer a wet-look with intense shine, shape hair with Poorboy's Natty's Blue (enticing bubble-gum)
On a more serious note, most of the smell created depends on the amount of oils generated by your scalp. Unfortunately, the amount of oil generated depends on a lot of factors (diet, weather, ethnicity, etc.) Your best bet would be to pay a visit to a dermatologist and have him/her diagnose what the leading cause is. Alternatively, you could ask "reputable" hair stylists in your area - They see so many hair/scalp-types daily that they are more than likely a reliable source for information. Obviously, they will also try to sell you $30.00 hair gel...