The Hunger Games by Suzanne Collins
I've now read The Hunger Games and Catching Fire. I'm glad I didn't start these while the trilogy was still a work in progress as I think the frustration of waiting for the next book would have driven me mad!
The books, particularly the first one, are tautly paced and gripping from the start. Collins builds tension very well and there were times that I found myself almost unwilling to move to the next page as I could hardly bear what was going to happen. The use of a first person narrator works very well here - seeing the world through the eyes of Katniss means that we are as in the dark as she is and we have to work out what is going on. We can speculate but we are as much at the mercy of the Gamemasters as the tributes are.
I've never read Battle Royale or the Running Man, so I can't comment too much on similarities. However, to assume that the concept of watching people fight to the death for entertainment is new is somewhat naive. The Hunger Games is merely a continuation of the Gladiatorial combat of ancient Rome and this concept has been revisited many times over in fiction and film over the years.
So far, I really like how Katniss has been drawn as a character - she's a stroppy teenager who pisses people off and makes poor decisions as well as being a heroine and a focus for rebellion. She can hunt because she's had to learn and she's tough because that's how she has survived so far. The other characters are nicely done as well - I have a soft spot for Haymitch and Cinna, along with Peeta.
Being a book for young adults, there are no detailed descriptions of the deaths but it doesn't need them. The facts of the Games are horror enough without graphic gore and Collins handles this very well.