[alvagoldbook]

I'd like to get a simple fixture for my 15 gallon. It's 24 inches wide, 12 high, 12 deep. I'd like to get more into the high lighting range so I can get some nicer plants. Any suggestions for what to get? I'd like to stay away from jerryrig/DIY options.

 

[2in10]

Get a 2 bulb T5 normal output fixture that will let you grow most any plant you desire.

This would be a good fixture just replace the actinic bulb with a 6700K or roseate bulb.
http://www.aquacave.com/24-aqualight-t-5-doublebr-strip-fixture-793.html

 

[londonloco]

Here's one for freshwater:

http://www.thatpetplace.com/pet/prod/209302/product.web