Recently, International Gymnast referred to Fabian Hambuechen (GER) as an “ambassador” of the sport of gymnastics. Which is very nice and all.
On the women’s side, however, I would nominate Verona van de Leur (NED).

She’s been Dutch national champion three times, and has had impressive results at the European Championships.
But more importantly, Verona seems to connect well to, and is friendly with, the other athletes. Her determination to take pictures with everybody at competitions is a good testimony to that. She even left birthday wishes for Nastia (along with Nastia’s fans) on Nastia’s website.
A good example of Verona’s camera work can be found in her 2007 World Championships album, where she has taken loads of pictures with other current/retired athletes; see how many you can find, it’s kind of fun.
(Verona van de Leur for Beijing 2008!)
I like Jade. She seems to have a true joy of competition for herself and for all. The real Olympic spirit.