I've read that your choice of top level domain can't hurt you, but in some cases can it help? For example if you had a site promoting Japanese tourism, would a .jp site do better than a similar .com site, all things being equal. I've noticed this for several searches of this type, but I don't know if it is due to Google giving preference, or if those sites just appear near the top naturally.
well if site is .jp then it got high Search result rank in Japan. Although .com is US specific but it is pretty used world wide
domain name and datacenter location makes a difference...if your doamin is .com and datacenter is in Japan u can rank well for both... make me correct if i am wrong