There IS difference between Western and Eastern Europe. But Eastern is too complicated to be seen as a single region. Some countries (Slovenia) are quite rich, even more rich than some Western countries. While some other countries are doing quite bad (Latvia) and there're many countries in between.
As of culture, South-Eastern Europe is very different from North-Eastern Europe. And Mid-Eastern Europe is totally different thing as well. Some are slavs, some aren't, some has more relations w/ russia, some w/ italy or germany. It varies from country to country A LOT.