Never saw this thread before. I personaly like the big age gap with my kids. My step-children are 12,11,10 and 7. I think it helps that they werent under the age of 5 because they are a tad more mature and find it fun to help with things, then again..they may be abnormal because they love doing house work(and IM not kidding!)lol
My brother and I were 6 yrs apart, and it was awful though, he beat me up all the time, I think that was because he was just an angry kid.