You know, I gotta say: A guitar player's true tone comes from his fingers and his own personal style. Chances are the guitar tracks sound like crap because the guitar PLAYER is crap. Crap in/crap out. It's that simple.
Do all the Line 6 haters in this particular post think that if Eddie Van Halen (or, really, any great guitar player) plugged into any Line 6 product that they would suddenly sound like crap?
I use my POD
and I like it. Don't love it, but I've gotten some sounds that work just fine for me. The clean channels are just horrible, but the dirtier ones can be tweaked to sound just fine. The reason why most people on this forum don't like the Line 6 stuff is because they don't know how to use it properly.
Now, as far as how to thicken up what you have I'd go along with what davedarling said. Sounds about right to me.