there goes my 2 cents:

Argentina is a great bargain. Have been there twice in the last year and going again. Great for a couple of weeks. side trips to Bariloche, Mendoza, Iguazu and/or Santiago de Chile.
Prague is no bargain but.... very good deal. Too small to hang around for 2 weeks, though

I may be biased as far as the next two but look into Bulgaria (in Varna look at the Musala Palace Hotel) - good fall weather, no crowds, incredible food and friendly people. Sofia is great all year round with many side trip possibilities including a 2-3 day side trip to Athens (not cheap at all)
My other suggestion is Israel. Great fall weather, very few tourists (after the Sept holidays), you can still go into the sea and there is enough sun to enjoy the warm days. Food is great and the people are..... well.... its Israel. Jerusalem is amazing in the fall sunlight. Instead of hotel, think about renting an apt. or an aparthotel.