Lonely Planet (reviewed here) is my favorite guide, especially since they became available as ebooks and I can take a whole stack of them along on my tablet or phone! They have sales every once in a while and for the next two days you can snatch any Lonely Planet ebook guide for only $8.99! That’s more than 50% off for most of them.
I just ordered three of them for trips coming up later this year – Tibet, Baltics and Poland! Jump on it while it lasts and let the travel planning (and dreaming) begin! You can start shopping here. Use the promotion code NOFOOLING in the shopping basket – it works for multiple guides, so shop and plan away!