With Amplitube, the amp model I got some of the most pleasing results from was the AC-30 one, for a nice thick distorted tone that could be rolled off on the low end as needed to fit. I was DI'ing in through a Great River with the input transformer cranked as well.

And you really do have to get out of the pre-sets, and also turn off matching in many cases, so that you can mix and match pre-amp and power-amp and EQ sections. That makes for much more flexibility.