I'm all for dialogue being written like true speech to an extent. Wanna, gotta, that sort of stuff. It can make or break a character. Particularly when you have one character that speaks like that and another who will always say "want to" and "going to".

It helps to define them as well as giving you more options. For instance, if the character that usually says, "I'm not gonna do that." suddenly spits out, "I am not going to do that!" you know he really, really means it.

I draw the line at accents, though. One of my fandoms has a guy with a very distinct accent and I find it off putting when people try to write it the way it sounds. For the most part, it's very difficult to write the sounds. The other major problem is, you spend more time trying to figure out what those letters spell than you do reading the actual story. I can supply the accent in my head, I just want to know what the character has to say.

Also...I love ellipses. They're valid punctuation tools. They have their place. Not to mention the fact that you can't get by without them if you write Ray Kowalski. :)