Sunrise from Cadillac Mountain or along Schooner Head Road.
Marina at Bar Harbor.
Bass Harbor Head Light: Best angles are shooting toward the east, but you'll have to walk about 100 yards over rocky shoreline to do it. Light hits it all day, but is obviously best in morning and at end of day (grounds are open 9 am to sunset). Use the path to the left to get down to the water.
Get off the road. Acadia is a prime example of a national park where the loop road does not show you the best stuff. I highly recommend getting onto the carriage roads, either by hiking or biking (depending on how much gear you need to haul -- you can rent very good bikes in Bar Harbor). There are some great views of mountains, valleys, lakes, streams and stone bridges along the carriage roads.
Check out Jordon Pond at the boat launch in the morning. It's at the south end of the pond off Park Loop Road.
Also, a little-visited part of the park is across Winter Harbor on the Schoodic Penninsula. Interesting rock formations and flora at Schoodic Point, but I wouldn't bother making the drive unless you've got really good light to work with or if you just want to make a nice drive (it is
a very relaxing place to just wander around or sit for awhile). The road that loops around Schoodic Penninsula has some great scenic views, too.
If you do head over to Schoodic Penninsula, also check out Birch Harbor (there's a good deli there, one of the few places around to eat), Prospect Harbor Point Light and Corea (a nice little fishing village).
If you have any questions, feel free to email me.
Chris Nicholson, NicholsonPrints.com