He reaches over, appropriates Jeremy's scotch and downs it, apparently entirely ignorant of the fact that this is a fairly large violation of the rules of etiquette.

I misread this as:

He reaches over, appropriates Jeremy's crotch and ...

Right. Moving swiftly on ...

The Captain Jack Harkness in Torchwood is far too different from the Captain Jack Harkness in Doctor Who for me to feel entirely comfortable when writing the character. I don't know how to reconcile the two characterisations.

Same here. It doesn't help that in 'Utopia' RTD appeared to reconcile the two characterisations by ignoring the Torchwood one. Good old Rusty - he does love that big old reset button! I'm interested to see how Jack is in Torchwood series 2. Less angsty? More angsty? The same angsty? Because I sure as hell would not be feeling frightfully chipper about the year that Jack's just had.

GWEN: So, what happened?
JACK: I went off with my old mate, the Doctor. The man I really, really love.
GWEN: That's nice.
JACK: No, it wasn't. He said I felt 'all wrong', on account of the whole immortality thing. Kept giving me funny looks. And then I was held prisoner by the Doctor's arch enemy, the Master. He spent a whole year torturing and repeatedly murdering me, just for fun.
GWEN: Well, that must have made the Doctor very angry and sad.
JACK: No, it didn't. He forgave the Master. Didn't even ask him to say sorry. And the only thing that upset him was when the Master refused to regenerate and died in his arms.
GWEN: Your old mate's a right bastard,isn't he?

Well, something like that. ;)