There are no rules for what your describing.
Most houses with 5" base and crown lends to more of a traditional look. That being said I would suggest colonial 5 1/4" base with a shoe molding. Add a fascia and a 4 1/4" colonial crown that is convex where the cove detail is on the bottom to make a complex crown. Then change your window and door casings to a 3.5" Windsor casing.

There are 100's of profiles but the ones I mentioned above are the most typical and stocked at most lumber yards.

Good luck

Crown molding in my opinion should be concave, or straight but angled between a 30 thru 45 degree angle. Agreeing with goodhouse on first sentence...the only rule when it comes to molding is what looks good

Thank you both for your suggestions!

GoodHouse- Do you happen to have a picture of the crown molding you are describing?

Check this website out for explanation so you can see what I am referring to.

http://www.windsorone.com/moldings_Colonial_Revival.php

This is my personal dining room. I have concave crown molding but you can get the idea.

Thank you!! I really like the colonial look. As for the fascia you mentioned above, what would be the most appropriate width for an 8 ft ceiling?

Thank you so much!! I love the idea of adding different pieces to make the molding look more ornate. I stopped by Home Depot and they had a display of exactly what you described which was helpful to see! I appreciate your help!