Do you feel differently about your nieces and nephews from your siblings compared to the children of your spouse's siblings?

No, I love them all the same. Children are so so special, I’ll take any one’s I can get. :)
Does that sound oddly psycho?

I am closer to the ones on my “side” because they are more similar to me in personality and interests. Also, the others live in a foreign country.

I don’t have any nieces or nephews from “my side” as I’m an only child – but I will say this… I have a niece and nephew and three grand-nieces from my wife’s side – and while I love them, I could easily take them or leave them. We have history together through my marriage (25 years and 2–5 years respectively), but I just don’t feel this amazing bond with them like I probably should. They’re great kids like other people’s kids are great kids. I see nothing of myself there though.

Her only sibling, her brother, is pretty much a ne’er do well. He’s got no kids, no job, no nothing except living off his mother. So it’s not an issue for me.

I have a lot of siblings and I am closer to some of my own siblings kids than others. It really depends on my relationship with the parents and even the age of the nieces and nephews. Some are almost as old as me and we grew up together. Our relationship is different than my relationship with nieces and nephews that are the same age as my kids.
Some lived in my moms home town and I saw them more than the ones that lived across the country.
My husband only has one sibling so the connection and communication is more frequent than with the mob on my side.

Not really. I’m probably a little closer to my sister’s daughter because I lived with her for the first 7 years of her life, but I’m not too big on kids either way.

I can’t help you. I have no nieces or nephews of any kind. I’m not married. Never have been. Probably never will be.

I adore my husband’s niece, mostly because she is only 10 years younger than me, and she and I are very alike in interests and style. In a few years, I think we’ll be great friends. His nephew… meh. He’s a nice kid and all, but I’m not really close to him in any special way.

But I’m already UberAuntie over my brother’s kid, and Blastocyst won’t even be here until mid-late May.

I love them all but blood is thicker than water. I like this question and have no other reason for the difference in my feelings and bonding with the nieces and nephews.

My siblings have no children. My wife no longer gets along with her siblings, but there are three cousins on that side. They get together occasionally so the cousins can see each other. The adults act nice for a few hours, but there is bitter resentment stemming from disparities in who had to take care of their mother while she was declining.

Since I’m not related to my wife’s nieces and nephews, I think it is natural that I do not feel as fondly about them as she might. I’m sure I would feel closer to my sibling’s children, if they had any. But they don’t. Life goes on.

Yes, but only my wifes sisters kids, not her brothers. Could be because they take after their mother and are self-centered little twats.