The 'Students and Travellers Inn'!! Expensive (14000 a double room, no WC), shared bathrooms were dirty, and people working there were not friendly at all.
Walk 50 meters and you'll find the Phaedra Hotel which costs 11000 dracmas, though also very old, has clean rooms and clean bathrooms! And the family there is very polite and helpful.
I do recommend the Lonely Planet guide, but it certainly is mistaken in recommending the 'Students and Travellers Inn'. Please believe me!