Yikes! I go away for the weekend, and there's a whole new board!
I was glad to see that my post on the old board generated some healthy debate. I appreciate all the feedback. Let me give y'all some closure on the original situation.
For the 55 I'm setting up I'm leaning toward a Filstar XP2 canister, pressurized CO2 (I found a reconditioned 5# bottle sold FULL for $35!), and the 130w Coralife strip I've already ordered from hellolights.com. They said they would swap out the 50/50 bulbs and put in 6700k daylight bulbs at no extra charge. Until it arrives I'm trying to keep my faith in human nature that they actually did.
I was interested in the argument that CO2 isn't necessary, but I think I want to try it. The budget can cover it and I'd rather invest in it now rather than wait and see if my plants need it. I think the sheer number of people who have posted on this and other boards about how their plants were more vibrant after adding CO2 makes me willing to spend the $ on it.
Surprising update: the wife is now getting into my project a little bit. I brought some rocks home from the lake and was cleaning them and she got interested in how to arrange them etc. She even suggested that we could put the tank in the living room instead of hiding it upstairs!