Though some people, including Subaru's marketing team, would like people to believe that the Outback is a crossover SUV, I know better. It sits low like a car, it's based off a car, and it has a hatch in the back, so therefore it must be a station wagon.
There have been three generations of the Outback. The first lasted from 1995 to 1999, the second from 2000 to 2004, and the current one from 2005 onward.
The base engine on this car has been a 4 cylinder boxer engine. A six cylinder boxer was introduced with the second generation, although the four cylinder engine was still the standard.
The Outback has become more powerful with each generation, and there is no reason to expect the fourth generation to be any different when it is introduced in 2010.
Whether you are looking for the standard model, the Limited, the Sport, or one of the many other trim lines, finding a decent used Subaru Outback to buy is not too difficult. Check current prices using KBB and also adjusting based on what you find on eBay (I like to do my research this way to find out what people are paying).