My fiance are trying to decide between two places. We aren't religious and don't want to get married in a church.

1. The state Aquarium.

Pros:
a. We love aquatic life and aquariums and my fiance is crazy about our aquarium and takes pride in it.
b. It would be unique and would express us.
c. The aquarium admission is expensive and it would give our guests a chance to see it for free.
d. fancy catering.

Cons:
a. 1.5 hours away from where we and most of the guests live.
b. Ceremony is under a fancy aquarium but isn't as fancy as a chapel setting (no stage or pews).
c. I'd have to find my own DJ, minsiter, and cakes
d. Total cost (including vendors) is about $500 more than option 2.

2. Local Chapel

Pros:
a. Close to home
b. All inclusive package
c. traditional wedding setting.
d. $500 cheaper than the aquarium wedding
e. More dates available.

Cons:
a. plain
b. simple hor de vours instead of a meal
c. Not as many options.

Which one?
option 1: http://www.okaquarium.org/index.php?option=com_content&task=view&id=37&Itemi d=642

option 2:
http://www.myweddingchapel.net/weddingchapel/settings.htm

I would go with the Aquarium. It would have a more personal touch to it. 1.5 hours is not really that far, people drive more than that sometimes in daily traffic and the $500 difference probably isn't that much in the overall price of a wedding. Think about the great pictures you'll be getting with the aquarium background!

After reading your pros and cons it seems obvious that you want to have it at the aquarium. Just by the way you described it, it describes who you are as a couple. Its unique and people would remember it. It doesn't matter if it is farther away because you are going to be there for a good length of time so people won't mind driving there for the ceremony and wedding.
It is not hard to find a minster, cake or dj on your own. You just have to do some research. Go to the knot.com they have a section that helps you find local services. Good luck, I would do the aquarium.