Haha wow, this topic was way back in the day when I was a n00b. Oh well, I might as well re answer that since I've experienced more coasters since then.
Okay, actually my answer hasn't really changed. I still like floater more, but the best airtime I've ever experienced was on Shivering Timbers, which was basically like, you slam up into the restraint and then stay there. It's a mix of the two (more so floater though), and it's amazing because on each hill you get at least 6 pure seconds of airtime. Incredible, really.
Unfortunately, floater can be extremely boring and dull on some coasters too, whereas ejector is constantly extreme. Millennium Force has some weak floater, and I just wish it had more, then it would be the ultimate roller coaster, but too bad, all you get is like, an inch off your seat basically only 3 times in the whole ride (not even 3 really). Ejector is always like "whoa save me oh dear lord I am going to die", which is pretty exciting.
But as of now, floater remains the favourite!