There are not that many wagons to choose from today, but my top 3 would be: Volvo V70R (300 HP, 6 speed manual and AWD), Dodge Magnum and the Subaru WRX Impreza. I have always been a Subaru fan and one of my firsts cars was a dull, but fun 1991 Loyale wagon.
Biggest sellers over here in UK is probably Mercedes, Volvo and Peugeot. Estates seem to be going out of fashion due to MPV and SUV sales increases. I do like the new Chrysler 300c touring which is available over here in right hand drive. Recent big seller was the Rover 75 tourer, but the company went bang last year though there are still a few new ones around.