If you can afford an FR-S get the FR-S.. (or BRZ) - Be prepared to be one of the guinea pigs tho as first year models may have some problems or the ones released in the next few years will get better / cheaper or whatever. However if the info is correct you'll get great MPG.
Don't forget these reviews that praise the car may not be 100% accurate since the car isn't out in production just yet so take them with a grain of salt.
If rear seat space/access is important to you and don't mind worse mpg, consider an RX8 R3 also if possible. If you're buying new you don't have to worry about reliability since the R3 is as best as it gets at this point.
If you're short on cash and FR-S is out of your budget and can buy used, consider a Miata or 1st series of RX8. Perhaps an S2000 instead of a Miata if you like that.
Anything else besides these and you're not in the same kind of car
I'd stay away from the Hyundai personally - As good as it sounds on spec sheet, it feels quite cheap and it's a Hyundai (I'm not a badge snob but at least Toyota, Subaru or Mazda have some heritage). Also it's ugly and not special enough. - It's one advantage is that it's turbo from the factory (I'm guessing its easier to squeeze a few more power out of it).
I'd also consider a Mazdaspeed6 if you can find it. It's classy, lots of room + luxury and it's AWD with 265hp if im not mistaken. Better than the FWD Mazda3 in my eyes
If you're straying away from the balanced RWD sports cars and going for more power + cruising the Mustang isn't a bad choice!
If you ultimately want the FR-S though, consider settling for something else for a couple of years in hope of a turbo/supercharged version or stick to your Camry if you can put up with it
The most important aspect for me that will eventually drive away or towards the FR-S is the aftermarket support and possibility of forced induction. That will require time and patience though, however you can take a leap of faith !