Here's my favourite recipe - it's by Nigella Lawson in her Feast book (the chicken pot pies recipe). It's really simple and the results have been consistently excellent!
450g plain flour
225g cold unsalted butter
2 eggs (plus 1 extra for glazing, or alternatively use milk)
Put the flour in a bowl, dice the butter into cubes and add it to the flour. Give it a gentle shake to coat the butter, then put it in the freezer for 15 minutes. While it's in there, beat the two eggs with a tablespoon of iced water, and put this mixture in the fridge.
Put the butter and flour into a food processor and blitz until it looks like fine breadcrumbs. Slowly pour the egg & water mixture into the processor while it's running until the pastry comes together. If you need a bit more liquid then use iced water - you want it to just come together in a ball.
Wrap the pastry in cling film and put it in the fridge to rest before using. You should have enough for two pies (4 servings).
The pastry melts in your mouth when it's cooked, yum!
It also freezes well if you don't want to use the whole amount at once.