The tractor I own (a small BX24) is a totally different breed from what you're after, so I can't really offer much as far as relevant tractor advice. But I can suggest that you work out what you need before deciding on a brand.
Also, as far as getting the most horsepower you can, I don't know if that's necessarily the only thing to look at. I'm not sure if this analogy will translate or not, but I recently got rid of a nice 300HP car and got a lesser HP Chevy Tahoe. While the Tahoe has less power, it has all the functionality I needed: support for a car seat for my daughter, 4WD to climb my mountain posing as a driveway in the winter, the ability to tow my BX, and, of course, great gas mileage.
With what I spent on my BX, I probably could have gotten a much more powerful tractor, but without a loader and backhoe, etc. So, what would I have done with the extra power, but no implements? However, had I not had an immediate need for a backhoe and could have gotten by with a loader and a 3pt implement or two, I would have gotten a larger, more powerful tractor.