I'm planning to register a domain with name xxxxx.com (sorry can not disclose domain name) but this domain is owned by some company. But xxxxx.net, xxxxx.org, xxxxx.biz domains are already booked by some one else not by same .com company. can I book domain xxxxx.US ? will there be any legal issues from other domain owners?
I think if the name is not Trademarked, you have no problem at all. Check this thread, there's the discussion about registering .us domains. Thread: HERE
I think your best bet would bet to get a different name altogether to prevent possible future complications. Plus .us names are not very memorable. I would stick with a .com for sure in this situation. Check out domainsbot.com for help with domain name suggestions.