Hey - my favourite for a meze is at Avenida; I'm afraid that I can't remember the address but it is about 150 metres away from Pefkos Hotel, which is on Misiaoulis & Kavazoglou Str., and only about 500 metres from the KEO Brewery on Franklin Roosevelt Str.
The food is fantastic, the service is great, the prices are cheap, and you will never manage to finish it all !
p.s. sorry if I have mis-spelt the street names -- I am doing this from memory, and I am a couple of thousand miles away.