Alisos,
have lunched at the Gallini Taverna every year we have been and its almost a tradion now.
The grub is superb, the pace is mellow, and every time we are there its at least 3 hours - quite marvellous.
There is another Taverna next to Gallini but have never been, so can't comment.
If you snorkel, the beach at Souda up by the rocks is superb and very safe. Its a bit cloudy sometimes close in, but once you get out a little the water is crystal clear.
Have a great trip, enjoy as am sure you will.
From a very jealous
Pritch