I found a really nice bookshop in the centre of Athens, Voulis 32, close
to Syntagma Square.
Here you can find almost all LONELY PLANET Guides, also Rough Guides and
Footprint and lots of maps from all over the world, even some countries
like Afghanistan f.e.
The staff is really friendly and offer you any help you need.
Recently they got new editions of Lonely Planets and maps and have a huge
pile of the old onces.
If you ask, you might get them for 1 Euro or even for free.
For more informations about the shop: www.anavasi.gr