Good thread, just thought about creating the one..
I expect few tight and very interesting matches..
I think Italy - Croatia is most exciting. Seppi is in good shape now. And if he wins against Cilic, it could bring big problem to Croats.
Then Canada - Spain. I would not pick either safely, may be Canada with small margin (considering they play in Vancouver, indoors hard). Raonic should score at least 2 points.