Since the Angels have pulled their 5 year, $70 million offer (though they apparently would like to sign him still) and there doesn't seem like there is any other team bidding for him, it might be worth inquiring. Like Southpaw points out, Safeco Field in Seattle was a spectacularly bad place for him, or any fly ball hitter, to play. Rogers Center, on the other hand, would be a pretty good place for him to play.
As an offensive player, he doesn't walk as much as I'd like, but then we have a lineup full of guys like that. He has good power, especially when he isn't playing in Safeco. At worst you should get league average offense out of him. At best? Last year he hit 28 home runs, 49 doubles and had a .321 average. His last two seasons away from the Pacific Northwest were MVP type years.
His defense? He's going to make some errors, all 3B do, you try throwing a ball that far, on the move, in a hurry and see how you do. He made 19 errors last year. But he has two Gold Gloves and would have more if they allowed people who care vote on the award. He is as good a 3B as there is in the game.
Normally I'm not a defense first person as far as third basemen are concerned. The guy at third gets 2.5 to 3 chances a game, so given the choice, I'd go with a player who can hit over one that can field, within reason. But then the Jays will have a young pitching staff, for the next few years, with many ground ball pitchers. Giving them the best possible infield defense might be more important than it would be for the average team.
Factored into all that is the two most likely 3Bs currently on the roster are below average defensive players and that gives Beltre a little more value to the team.
The downside to signing him? It would likely take a 5 year contract in the area of $13 million a year. A pretty nice area for anyone to be in. He turns 32 in April, so you would still be paying him $13 million when he is 37.
The other downside is third is where I thought the Jays planned to put Brett Lawrie, likely not this year, but maybe in 2012. Closing off third means that Lawrie likely would end up in the outfield. But the outfield could be crowded too. If Beltre is at third, if we wanted to resign Jose Bautista after this season, he'd have to stay in RF. With Jose, Vernon and Travis it would be hard for Lawrie to break into the outfield.
Anyway, let's put up the poll: