I wouldn’t go into full on make-out mode right in front of the Commander, but a quick peck on the lips? No biggies.
This would change if my SO worked with me, specifically if he was a higher ranked officer.
Not a big deal, to me… the only caveat would be if you work with clients in a specific setting in which a show of romance or intimacy might be in poor taste (e.g., a kiss good bye in the waiting room of a clinical psychologist or a divorce lawyer).
I work in a library, and I don’t think a quick peck is that big a deal - my husband drops by maybe once every three months or so, and we kiss goodbye when he leaves. However, we’re out in a branch location, and we’re a little more relaxed out here.
Now, tonsil-hockey is a totally different story. That’s pretty much nasty anywhere in public, work or no work.
Years ago, a co-worker and I would bet a buck whether there would be a kiss when someone’s significant other stopped in. There would be the occasional visit near the entrance to the work floor. So one of us would tell the other, “a buck she kisses him,” or, “a buck there is no kiss.” We could do it only once per person.
Usually, there was no kiss. Those that did kiss were usually older (30+, which seemed OLD to us young guys at the time.) Any younger guy who got a peck would seem moritified when he turned around and realized someone witnessed it.
A few times, the loser of the bet would ask the guy about the kiss or lack thereof. The older guys would say, “She’s my wife. I love her. If she wants a kiss, she gets a kiss. Nothing wrong with that.” The younger guys would typically say something like, “Why would I kiss her? I’m at work.” The girl employees usually kissed their guy and didn’t have a care about it one way or the other.
They were talking to each other and occasionally smooching in the middle of the conversation. You don’t think that’s odd? Does it happen often where you are? Maybe we’re just cold Northerners or something (but we’re warm at heart) but that was the first time I ever saw that behavior. You can behave professionally when you are at my office trying to sell me something, please, and that does not come under my heading of ‘professional’.
Posysn, that would be a totally different definition of ‘saluting’. Although I suppose you could have some really fun bedroom games. 
“Sir! Yes sir!”
Unless you’re doing full-on tonsil hockey, or it’s in front of The Big Boss, or something, then no biggie.
This of course is coming from the person who once made a male Partner (high-rankiing person in an accounting firm) kiss a male co-worker on the cheek :). See, he had just done the same to me (congratulations on being promoted), and the male colleague who’d also been promoted was standing there, and I said “uh-oh, harassment” (or similar).
I would have voted ‘kissing is expected’ but that wasn’t a choice.
I work in an office; the front desk staff know my wife on sight. On the rare occasion I forget my lunch during the summer (she’s a teacher), she’ll bring it by for me. On the even rarer occasion that she does so and we don’t smooch when she leaves, I get grilled by the nice, older receptionist.
On the extraordinarily rare occasion that I visit her at work during business hours, we still kiss when I depart, even though there’s a classroom of freshmen as an audience. I’d like to think it grosses them out, but she tells me they think it’s sweet.
No problem with a kiss (from the spouse, not a co-worker of course) 
The thing that DOES make me completely ILL and want to heave my body from a cliff is my cube neighbor who talks to his wife on the phone 5-9 times per days and says ‘I love you’ NON-STOP. He likes to think that women who overhear him think he’s the “good husband that we all want to have because he’s so amorous”. PUKE.