Hey! a 75g isn't a nano! What were you thinking?
Good choice. I would say reef tanks are quite a bit more expensive than FOWLR tanks, though. There are many other costs associated with reef tanks vs. FOWLR tanks other than lighting -- i.e., calcium supplements for corals, phytoplankton, etc. I think in the long run, you'll be happy you chose a reef. I agree with your reasoning, too -- a 75g fish only is rather limited. I think the whole point of having a fish only is getting those awesome tangs and puffers and lionfish, no? If it were a 125g or bigger, I'd would choose FOWLR.