I'll post some more this afternoon. Thanks for the great feedback. I'd like to thank Jean-Marc Ferriere (RFF jmanivelle) for being a great guide and my new friend in Rio.
I didn't take the T3, because I decided at the last minute that I didn't want to deal with film for the trip. I actually had the camera, batteries, and film loaded in a bag when I pulled it out before leaving the house. I figured if I needed something REALLY discreet, I'd have my iPhone...yes, sadly, it would've probably worked fine for a few things. Luckily I didn't need it (though it took some great Hipstamatic shots...love that app).
Rio felt safe for me, but here is the reason. Jean-Marc had a car and knew the area, as well as obviously speaking Brazilian Portuguese. If I had to take public transportation, without language knowledge, my stress level would've been much higher. Of course, I was traveling by myself, so ANY travel companion would be added safety. Also, the G20 (?) meeting was about to start, and there were police everywhere on the beaches. It seemed the tourist areas were ok after sundown, but I wouldn't want to walk back from those areas to my hotel (the Sheraton, on the edge of Vidigal favela). In fact, last year there was a shootout in the lobby of the hotel I stayed in (and it's a very nice hotel). So, there is always a nagging sense of "what if," but I really felt safe at Sugarloaf, in Niteroi across the bay, and even on Ipanema and Leblon.
I hope that accurately paints the picture I felt as an outsider visiting there.