Well, of current Aussie cricketers, it might seem a strange choice, but Glen McGrath's always seemed a fairly nice guy to me. I know his behaviour on the field hasn't always been the best, but he does have a rep for being quite a jovial, friendly guy off it. His wife also seems nice and genuine, and doesn't have the same air of uh, how you say, "trophy" about her as some of the players' wives/girlfriends.
Outside of that, I wouldn't mind spending time with Steve Waugh - I like his sense of ethical responsibility, I'm pretty sure I like his politics, and I admire him an enormous amount as a cricketer. Other players that come to mind are Greg Matthews, Carl Hooper, Phil Tufnell and The Shoaib.