Lily Photo Index
I was also having trouble figuring out what was the difference between Asiatic and Oriental lilies. Snow Creek Gardens website (which has its own very nice collection of lily pictures) had a pretty good explanation:
Asiatic Hybrids generally have in their background many different Lilium species which originated from several areas of Asia. They are early-bloomers, usually with no fragrance, but multiply rapidly. Asiatics have the greatest range of colors and more variance in flower shape and bloomtime.
Oriental Hybrids were developed from only a few species native to Japan. They are heavily scented, with much larger flowers, and bloom later than most other types of Lilium. Many Oriental lilies have raised papillae in the petal nectaries. This "starfish-looking" characteristic will, at times, have yellow or crimson accents. Oriental bulbs tend to increase in size, with taller stems and more blooms each year. Because they slowly produce multiple bulbs from natural division, lift and divide bulbs every 3 to 5 years, or if stems become crowded.
Well, that helps, but I don't think it gives me a clear enough picture. If you have any extra information on this, please let me know.