I'm gathering from this thread that most people think the social aspect is a huge consideration, and I would not necessarily disagree, but right now (ha! about a year or two into this whole gifted issue thing) we are thinking that the best thing for DD8 is to try to help her develop her positives (in her case so far, math ability) and hope that eventually the social stuff will catch up (we are working on that, too, of course). It has been suggested that she has a variety of disorders including Aspergers, but although we would agree that she probably meets at least 2 and possibly 3 of the "A" category criteria, we do not agree that she meets any of the "B" category--and so is not technically an Aspie. However, she does have significant social difficulties even though she has several good friends and usually gets along pretty well with most other kids at school. Regardless of where they fall on the spectrum, though, my personal opinion (which may well change drastically in the future! Heaven forbid) is that if a kid is asking for more advanced material, then they should get it if possible. The social stuff may be difficult through high school regardless, but once people are in college and beyond they're much more likely to find their social niche (as I did) and at that point I think they are best served by having developed their skills to the best of their ability (and inclination--not advocating any kind of pushing here). Our DD may never "fit in" in many social situations, but I am convinced that once she is with people who are more like her (i.e., 'math geeks'), she will do great and I want her to have as many choices as possible for future schooling/profession, etc., so that she can find a job/career that will help her feel fulfilled and happy.
Just my opinion; of course every kid is different and you know your kid best.
Best of luck for and with your DS!!