There are two main arguments here (that I can see, anyways).
1) You're better off than they are because you were born that way. How is getting born your fault? Why should you have any guilt about that?
2) That somehow your position is built on keeping the rest of the world down. Uh-huh. Can't see this one either. Having lived in Africa and now in Europe, I just can't see that it's the responsibility of the West to keep the starving masses of Africa or China (or wherever) fed and clothed.
Maybe it's racist/classist/someother-ist, but from everything I can see most people are in the position they are because of the choices they make. Sure, you don't choose to be born African (for example) - but they sure as hell choose to do nothing about it. In all of Africa, there are only TWO (that I'm aware of) countries that have been even vaguely successful since they achieved independance from the 'imperialist oppressors'. Every single other country has descended (often overnight) into chaos, anarchy, oppression (far worse than the Europeans EVER did - look at Zimbabwe), dictatorships, coups, counter-coups, war, rebellion, guerilla terrorism etc.
It is a fact that more people are murdered in two months in South Africa (and that is one of the SUCCESSFUL countries) than have died in the entire 30 years of war in Ireland. http://www.davidduke.com/general/17807_17807.html And the vast majority of these are perpetrated by Africans ON other Africans.
Having been mugged twice, had my house broken into three times (once while I was there), having had my mother assaulted in the streets, and my father hijacked at gunpoint - I'm just glad I got out before they did it to me.
So no. I don't feel guilty at all. They do it to themselves.