Sorry guys, the comments re Belgium are way wide of the mark. True, the airspace looks intimidating (as does the NE corner of France) but ATC (both civil and military) provide a superb service. Unfortunately, due to a master political stroke, the country has lost one of its' aviation gems; SPA airfield closed without notice last month.
Having said that, France gets my vote; plenty of fantastic destinations and always a helping / welcoming hand close by.
Spain is fine as long as you avoid the madness that is AENA. There are plenty of small club alternatives but, for some reason, their existence is not widey advertised.
It's been almost 10 years since I've ventured east but at that time Poland, Lithuania and Estonia were a real pleasure.