If you are looking for a post-graduate text (the books recommended so far are for undergraduates), then Gareth Myles, Public Economics is a standard text. The text by Atkinson and Stiglitz, Lectures on Public Economics, is better in many ways, but much older - there is a 'updated' edition but it is simply the original text with a new introduction. Intermediate Public Economics by Hindriks and Myles is newer than both above, but it is aimed at upper level undergraduates.