As a German who loves travelling. It's a veery hard question to answer. As weird as it may sound, I would probably choose getting a russian visa. This country is just so big, and after being there 2 times already and not even seeing everything in Saint Petersburg and Moscow, a lifetime visa would be very helpful.

Also, it's relatively hard to get a visa to russia. The first time I got it it was a big problem for me, but on the second time a russian friend of mine introduced me to an agency that's helping you get a visa to russia. She actually has her own blog about Russia and ways to get there, [url]hellorussia.co.uk[/url], check it out if you are interested in the country as much as I am.