You can get through 90% of the dialogue in the game without even reading or listening to it and still get the desired morality rating.
I have been playing Mass Effect quite a bit and I am really engrossed in the whole conversations.
I've mentioned this before, no? The last time someone talked about our dialogue in an interview, I suspect. Even so, it's worth repeating.
The dialogue is presented in exactly the manner that you'd be accustomed to, having played NWN or BG2. You're presented with your exact words (or actions) to select from in dialogue. The similarities to Mass Effect come in when you're looking at the level of detail in the emotional response and animations. It may not seem like such a big deal to some, but for us it's another tool that we simply didn't have to any degree of sophistication previously (if at all).