nslookup and dig are great DNS query tools, but my favorite simple cmd line tool is 'host'.
host domain.com [name server]
Want to look up NS, A, or MX records for a domain?
host -t ns domain.com host -t a domain.com host -t mx domain.com
Want to look up all available records?
host -a domain.com
Give it a try. You'll like it.