I'm on a quest to produce the perfect blueberry pie. I made a pie earlier this year that was too sweet (the flour to sugar ratio was too low) and that didn't cook enough - most of the blueberries didn't burst and congeal in the pie. I may have put too much butter in as well.
Round two was just pulled from the oven. Here's a snap:

Here are the ingredients and directions:
Ingredients
4.5 cups of blueberries
1/2 cup of sugar
1/2 cup of flour
2 teaspoons of cinnamon
Juice from 1/2 a lemon
1 ounce of butter
2 pie crusts
Pre-heat oven to 450.
Wash and dry the blueberries picking out any funny colored berries and ensuring all berry stems are removed. Set aside.
In a fairly large bowl mix the sugar, flour and cinnamon. Stir. Then add the blueberries to the mixture and continue to stir until berries covered.
Pull the pie crusts from the freezer and put one crust in the oven for ~1 minute or two until it begins to soften (not cook!!!) Then pull it out.
Pour the berry mixture into the still frozen crust (saving about a tablespoon of poweder in the bowl) and squeeze the juice from the lemon over the top of the unbaked pie. Now slice the butter into small buttons and dot the blueberries to ensure good coverage upon melting.
Flip the slightly warmed pie crust over the top (may want to loosen first) and pull it out so it is centered over the pie. Don't worry if it isn't perfect. Doubling over adds character. Slice 5 slits in the top crust and sprinkle the remaining tablespoon of sugar/flour/cinnamon mixture over the top.
Put alumnimum foil around the crust edges (usually takes about three strips) and place pie in oven. After 12 minutes, reduce the heat to 350 and continue cooking for 40 more minutes. Then remove the foil strips - if it looks like you can cook the pie for 5 more minutes do so.
Tasting report to follow.
Update on the 2010 edition. Again the above produced a "perfect pie". I actually forgot the butter this time and it was still very good. Took the 2009 advice and did a better job sealing the two crusts in the middle. You can't really beat this recipe. Here's the picture of the pie - which by the way features Oregon berries. CA berries peaked a few weeks back.