Rob, you are the man !!! Absolutely release the fish. This is the only way a big fish can get huge !
And about your 15-12, I have personelly discussed this catch with several prominant fisheries exsperts, all of who agree that this fish was probably exceptionally young, and has tons of potential to get much larger ! You may have caught the future world record bass ! And what's cooler yet, is that because of your forsight, you may just catch that world record yourself !
I know many people think that this is a huge longshot, but I have personely caught and re-caught my biggest bass (a 12-11) and my good fishing buddy caught and released her too (but when he caught her, she went 13-2, that dog ....chuckles)! All over a period of 11 months !
And yes Rob, about a camera and a good digital scale.........I carry 3 cameras and 2 scales ! Never can be too careful.

Catch and Release a Trophy Bass !
Fish Chris