Just don't fall for the alumunum rear sprocket nonsense. A nice piece of maple would make a better and longer lasting sprocket than aluminum. Steel isn't durable enough, in my opinion. I see many examples of aluminum sprockets that are wasted in less than 1000 miles. I can do that in a weekend.
Going up one tooth at the rear will give a little bit more low end grunt and may even improve your 'real world' top end as well. For example with somewhat lower gearing you may actually go faster if you're going up a slight grade, or into the wind, or when riding double, or if you're as big as a line-backer, etc, etc.