Shower. Blade. No Fear.
(…no Way is it getting worse.)
Shower. By feel since I wear glasses and a mirror would be useless. If I’ve let the hair grow in a little (like over a weekend) I’ll take a nice long bath and give my face a good soak and shave in the tub.
I’m sure that’s all very romantic and lovely, but does someone else shaving you really produce satisfactory results? I’m just not convinced that any SO would be able to wield the razor in sufficiently contorted fashion to reach all the various angles required to shave my neck.
Shower. I’ve got a mirror which stays defogged long enough for a quick shave.
If I shave at the sink there are hairs, foam, water everywhere afterwards. I am a very messy person apparently.
I mostly shave in the shower, only using the sink when I need to be very clean-shaven.
It started when I got a medicated shampoo that needed to be left on my scalp for 3-5 min, and shaving gave me something to do while I waited…
Shower for most of it, dry touch up at the sink when I get out. If I want a really clean job, I’ll shower to soften the whiskers, then shave at the sink using shaving lotion.
Well, a lot depends on your insurance. 
I usually shave in the shower.
I voted everywhere because I’ve shaved everywhere, including outside. I have a chargeable electric so I’m not “tied” to the nearest electric socket so long as I remembered to plug it in to charge up. I like wandering around the apartment getting minor tasks done as I shave, and standing in front of a mirror the whole time would be a waste of time. I judge my shave mostly by feel but I do a quick look in a mirror as a double-check. I live in a '70s-era building; there are a plethora of mirrors to choose from. 
If I’m running late, I take my shaver with me and shave in the hall and the elevator when nobody else is present. There’s a convenient “check yourself” mirror on either side of the elevator doors. 
If I’m driving, I shave at stop-lights. A few times when I’ve been really late and taking the train, I even shaved as I quick-walked to the station when there was nobody else about (putting the shaver in my briefcase otherwise) and finished off in the train washroom if necessary.
That must’ve been quite the yeast infection!
I’ve got a beard, but I shave my neck. It only takes ~30 seconds, and it’s easiest to do it at the sink right after washing my face.
Shower. I have a little mirror suction-cupped to the shower wall at home, but if I’m traveling I do it by feel. After years of trying to shave at the sink and cutting my face, despite all manner of experimentation with different shave creams, skin bracers and what-not, I got sick of all the nicks. The only way I can shave without cutting myself is when my skin is its wettest and softest, which is in the shower. Oddly, just the water is enough; no soap or foam necessary. I’ve never nicked myself with this method.
Occasionally I’ll use an electric at the sink, but usually it’s a safety razor in the shower.
Shower, with a blade. I’ve got full-length mirrors on the walls so I can see what I’m doing (they don’t fog up much) but honestly I don’t need them except to make sure I’ve got the edge right at the top of my ears even. I just know my own face I guess.
In the shower. My face is already wet, and the hot steamy water helps soften my whiskers. And I just use my shampoo instead of shaving cream, so I save a couple bucks.
I initially misinterpreted what you meant when you said you’d “shaved everywhere” and thought to myself, “surely that would be easier in the shower.”
Really? I’m going to have to give that a try tonight.
I shave my face with a razor, have a ‘goat’ to trim around, need to cut any length way back with an electric and try to set a good example to my shower dwelling daughter about prudent water usage, so at the sink.
I shave in the shower, with whatever razor is on sale at Rite Aid. I’ve never had to use shaving cream (infact, it makes it harder when I do).
Dammit, this isn’t the type of thread I was expecting. Now lets change Gents to Ladies, and use a different definition of where.
Like I said earlier upthread, don’t let me cramp your style. 
I think we’ve had one of the other “where do you shave?” type threads fairly recently, though.
What about the wet hair? I mean, yes, my shaver can get wet, but wet hair is sticky, and clogs everything up in short order. Like I said, mine’s the type that encourages you to rinse it out to clean it, and that has always served to make it worse.