Any small tranquil villages with access to high speed internet and amenities and convenience in Europe will do.
Marbella, Malaga, Canary Islands has great weather year around. One also has to factor in other things like food, restaurants, night life, women, etc. Life is not all sitting in front of the screen. I know Marbella/Malaga area has a retail/ex-pro trader community. So it's nice to be able to make friends with other traders.
There are basically only two timezones: UTC (London) and UTC+1. So the timezone has almost no impact on the trading hours. So you can choose: start to trade at 14:30 or 15:30 (CME RTH). Taxes are not important to you? Because you did not mention it, and as rates can show big differences.
The Gran Canary or the Greek island of Mykonos are my picks for Europe. My favorite island is Maui where I live. Getting out on the ocean does wonders for my trading.
I'm trading from Thailand. It's nice here. No taxes. But trading hours for US market are a pita. I plan to move to Amsterdam. I love this town. But, as an expat you will pay too much for a flat or house. They have stupid conditions for non - employees. Otherwise maybe an Baltic state. Low living costs and excellent Internet.