Plenty of shops and great nightlife .Also an ancient theater in the middle of
the city.

I loved the nightlife -second to none in Greece- beutifull
cafes,restaurants even an ancient Greek theater and the best thing the center of the city is like a giant open mall just for pedestrians since no cars are allowed in the center of the city.
If you want the Greek experience without the hustle and headaches of a gigantic
metropolis like athens...not to mention a lot cheaper then
check out Larisa and with plenty of beaches closeby.