There has been a lot of pessimism among Buffalo Sabres fans about a team coming to Hamilton Ontario. The two state senators have even sent a letter to the NHL in opposition (they should be more worried about the Islanders). However putting an NHL team in Hamilton would be good for the Sabres.
First of all giving the Phoenix Coyotes to Jim Balsillie and moving the team to Canada will be good for the league as a whole. It would generate more gate revenue, and higher TV contracts (in Canada) coming to a net profit for the league as a whole (including the Sabres franchise).
The arena in Hamilton is within 50 miles of the one in Buffalo, so Balsillie would have to pay off the Sabres (and the Maple Leafs), giving Buffalo a good amount of money in this deal right off the bat. While this payment wouldn't be too huge it will be significant and would be beneficial to the Sabres organization.
Particular to Buffalo is the fact that an estimated 15% of the Sabres tickets go to Canadians. Many are worried that somehow having another franchise in Hamilton will reduce this flow of Canadians to the arena in Buffalo. The problem with this outlook is that many of these people are not Sabres fans to begin with. Most only come when one of the Canadian teams are playing (usually Toronto and Montreal) and stay away for the rest of the season anyhow. The Sabres have noticed this and raised ticket prices on those games, knowing that it had no effect on their average fan and only took money from the Canadians.
With another team in Canada Buffalo will only have more opportunities to take money from Canada. With an additional three home games a year against a local Canadian opponent, that is three more games to pack HSBC arena full of northerners and continue to make money. Games against teams from Canada will increase from 13% to 16% and gate revenue will most likely go up to match.
Don't worry, hockey in Hamilton is not a threat to the Sabres.