A friend of mine and I are talking about spending next summer working and enjoying ourselves in Europe.
We were thinking a city where there is at least some English speaking population, lots of nightlife, and its not TOO expensive.
Wow, it's tough to get all of those combinations. Try Athens, and maybe perhaps Barcelona. If you're keen on Turkey, try the coastal town of Bodrum - cheap, great nightlife, and great day trips to some of the Greek Islands.
I would suggest Antwerp, Belgium. Everybody is able to speak English, nightlife is excellent, it's a trendy city (Bikkenbergs, Van Beirendonk,...) and equally important: the beer is the best in the world
And ofcourse you're in the center of Europe so you can still go and visit Paris, London, Kopenhagen, Berlin,...
Amsterdam is maybe something for you. it's quite international, most dutch speak well english as second language, many foreigners there also. besides it's in the heart of northern europe with short distances between Brussels, London(by air), Paris(3 hours by train), and Germany.