There is no such thing as "Eastern Europe". That's a silly cliche back from the iron curtain era. Stop using it, as it doesn't make sense in any way. Not economically, not politically, not even geographically.
You think there's no difference between Western and Eastern Europe? Really? You insult both regions, and your pomposity is making me a little nauseated.
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.
The rest of the advice is pretty good, though.