is the most visited? Spain France and Italy I bet, they have good weather, they are big, very cultural... these countries have cultural tourism plus beach tourism.
most powerful economy? Germany... but it is just in general terms, if we talk about corck production then it's Portugal!!
most powerful military? Spain and UK
largest cultural contribution(television, music, etc)? UK, Sweden, Spain...
largest population? Germany and Russia.
biggest and best cities? Best who knows, what do people like?? and biggest, just look at wikipedia, Moscow (Russia) Berlin (Germany) Madrid (Spain) Paris (France) London (UK)
quality of life? Switzerland probably, o maybe Norway??
who makes the best cars? It depends on what you like, Germany, Italy...
best food? Portugal, Greece...