Torchlight is a steal, especially for people that steam uses the correct exchange rate for. It's one fifth the price of a new release in Australia at $22 AUD. Sweet. It's probably missing the gore effects though, I read there was blood in a review but I see nothing.
Multi would just bring on the griefers, hackers and dupers that would join my game. They can stay in D2 for as long as they like IMHO. (or in their own, isolated copy of Torchlight.)