deadwing, in my opinion, is a slightly heavier continuation of In Absentia.
In Absentia is an awesome album. but even it, for me is not the best porcupine tree.
for me, it's Lightbulb Sun and Stupid Dream.
however, if the heaviness is what you like, only In Absentia will please you.
Then, look for the Opeth albums that were produced by Steven Wilson at around the same time... Blackwater Park, i think, is the one to look out for...
I would also certainly check out Katatonia's "Last Fair Deal Gone Down" album. I prefer their newer/heavier/darker music, but there's no denying the aforementioned is nothing short of a genius release.
Skylab, you are spot on about the rush influence. Especially since gavin harrison took over on skins. Can you say "neil peart fan"?
And, i need to revisit the incident album. Foabp was a big disappointment for me, so i didn't give the incident a fair chance i guess...
So far, I have tried Crack the Skye, Train of Thought and Blackwater Park. I think these titles have pushed the boundary for me a little too far to the metallic side. I will give them a lot more time before I say this decisively, however.
I just received In Absentia and will spin it this weekend.