I do believe that the 717 will mostly be ordered by carriers which are first time entries into the jet business, I here recall the Regional Airlines (Spain) 717-200 order, maybe Olympic Aviation, too. I guess Jersey European might be one of it although I suppose a 115-seat version of the ARJX, "ARJX-115 called" (when the ARJ family was launched a 115-seater was offered, the RJ-115) would suit them more.
The A318 is more likely for carriers which already have an A32X fleet, I guess LH, UA, NW and US will order it.
The 767-400 will probably don´t gain much orders. Most of them will come from US carriers, I think Delta and Continental (have already ordered it), maybe TWA once their financial status recovers. Some smaller carriers, VARIG possbily. The A330-200 will get most of these orders, it offers a better performance compared to the B764 and has already gaind a lot of orders. My bets go for LOT, RAM, Tunisair, Britannia, NW, UA and Lauda Air.
The 757-300 is a problem for Boeing. Although I might be a bit too pessimistic I think its the wrong plane at the wrong time. Onyl few carriers (Condor, Arkia, JMC, Icelandair) have ordered a few and no customers are in sight at the moment. The only one I can think about is TWA but see above.
Now to the most interesting point: the A340NG (-500/-600). I think Cathay, Malaysian and Thai will place orders for it, maybe even Korean. Airbus will sell them in package deals with the A3XX I guess. The same what Boeing did with 777 and 747 deals. Just wanted to mention it so that nobody can say Airbus is doing something unfair. I can think about some deals here: United launched the 777 and got some 747-400 very cheap, Malaysian signed a huge 777/744 deal.