First, welcome to FT and have a great time in Brasil.

Safety: I treat Rio as I do any big city. Be aware, don't flash money or jewelry. Act like you've lived there 20 years.

Hotel: It depends on your needs. I stay at the Ipanema Inn. Probably a 3 on a 1-10 scale but the price and location is great. Should be around $30-40usd/nt with breakfast. It is about 200 meters from the beach and is just behind Ceaser Park in Ipanema. Ipanema is the place to be IMO. Beach, food, entertainment and shopping is all there.

Sites: Since you have only a short time see the major ones but be sure to visit the beach on Saturday or Sunday when all the locals come out to play. The Ipanema Hippie fair is also (used to be anyway) on Sunday.

Food: If you eat meat, fast all day and go to Porcaos in Ipanema for a fantastic Brasilian BBQ. More meat, salads, fruits/veggies than you could imagine.

Take your smallest swimmers and plenty of sunscreen and a big smile - you'll have a great time.

I prefer to use the ATM machine at the airport after arrivals. You can board an air conditioned bus that'll take you close to your hotel if you are staying near the beach. It's a great way to go and about $3usd I believe. Look for the bus just outside the doors after arrivals.