I think Floboy's second answer is rare, but first answer is very usual. One more very usual usage is politely saying to unfamiliar people who you are talking with. ( ex : When I say to you " What is your name? " / " あなたの名前は何ですか？" )

"anata" is used by... a wife addressing her husband. a girl addressing her boyfriend (less often, moer often is "xy-kun")

Not definitely..Depend on your tone. If you said very tender that will mean to lover. if you said very angry that will mean to strict to someone. hope you can understand what I mean.