If it was a killer name, I think I would grab the big extensions.
I used to often get the .net/info/biz etc for sites I was developing to prevent the competition getting them but my thoughts have changed on that. If you've got the .com, it might be beneficial to let someone else develop a site on one of the lesser extensions. Suppose their site became a big hit...who's sitting with the .com...*you* are!!
I'm in the UK. Usually the .com and .co.uk versions interest me the most.