The voltage in Greece and all of Europe is 220 volts/50Hz.
220v is twice as strong as US voltage and it can kill you! So be careful especially with wet floors and extension cords. If wiring seems faulty, smells or starts to smoke take immediate action. Turning off the main power at the junction box is a good idea if possible and safe.
This has never happened to me and probably wont happen to you but depending how deep in to the hinterland you go and how old the wiring is, it wont hurt you to take precautions and be on top your electrical situation.
I ruined a sensitive electronic recording studio due to brown outs and power surges here in Athens and although I was able to get it fixed, it cost me 325 euros. If you are going to be running equipment like that, or even do some serious work on a desk top computer then an 90eu uninterrupted power supply, or UPS, is a mandatory requirement. See my computer tips pages for where to by them (plaisio).
To avoid electrocution, the Greek building code (and one of the few codes they adhere to) states that there be no electrical outlets in bathrooms. If you are used to plugging your hair drier or electric shaver in to a bathroom outlet, some better hotels have outlets and or the hair driers themselves, somewhere about the hotel room. For men there is usually a special type plug in the bathroom. You need to be in a modern hotel for these kind of considerations.
In Greece and in Italy too, last time I was there, the plugs
are 2 pronged and round, so you'll need to bring an power adapter for your shaver, hair drier, Walkman,
laptop, etc. Adaptors can be purchased
at K-mart, Wal-mart, and so on. An
5 m extension cord (ba-la-dez-za) will come in handy also. Buy that by specified length here, if you need it.