Open necklines work best on me. V necks, scoop necks. I have a short neck, short torso, narrow shoulders and larger bust with weight gain. Sometimes a boat neck can work on me, because it draws a horizontal line across my shoulders. I do wear crew necks and turtlenecks if they are not tight, and part of layered look. For example, an open cardigan with "v" integrity. Sometimes I throw all of the rules out the window when I want to be warm and comfortable.

I am small, regular/slightly short neck, small bust, rectangular and slim. I sooooo prefer crew necks. I fun cold and I do not like too much chest exposed. I would be interested in a very high vee but they are almost never available. So I am a "crew" girl all the way!! Also they elongate my torso with a midrise pant which balances my long legs and long arms. Works well for me.

V-neck and scoop for me, but they have to be higher with no cleavage showing. I'm large busted but I'm also petite so often the neckline is too low for me, especially right now when it seems the style is to show it off. I can't stand turtlenecks, they just make me itch and according to the rules aren't my best look anyway and crewnecks often make me feel like I'm choking. I sometimes like a boatneck though.

Crewnecks for sweaters, Vnecks for tshirts and never ever the opposite

Wow, it’s fascinating how individual this is, not a matter of simple rules.

I’ll add my particulars:
Broad shoulders
Small, wide set bust
Short, straight torso
??? Neck (average I guess??)
Long hair often worn up

I strongly prefer scoop necks. V-necks are ok but something about a rounded neckline seems to suit me better. Crewnecks are SO BAD, the higher the worser. Boat neck can work if it is not too high - basically I need some openness to the neckline.

Oddly a turtleneck can work ok but they are hard to fit due to my broad shoulders - I often get a fold at the front of the neck which is uncomfortable pressing against my throat.

I prefer a crew neck. Most vees are too deep for me to be comfortable.

Slightly broad shoulders, small bust but wider chest, body shape is rectangle, long hair, average neck and I strongly prefer v-necks to crew necks, and I do not like deep scooped neck or u-neck for me (has a widening effect on my shoulders and chest area that I don't like). I do wear and like higher necks and some crew neck styles esp. when sleeveless and I like an envelope or boat neck as well, even though it's not necessarily recommended for me, I feel it works. Old school crew neck is my least favorite and when I buy a tee with more of a crew neck (typically graphic tees seem to have more of a crew neck) I often stretch it out on purpose.

I prefer crewnecks to v-necks, but I do mix them up and have some v's that I like. I think it's really a matter of personal preference! If you love crews, wear them

In theory v-necks should work better for me, but I prefer crews. I have seen to many pictures of me in v-necks when I unintentionally exposed too much I have completely purged them from my wardrobe.

Small shoulders and bust: crewneck always. I'm often making small alterations. A little bit tighter, move a button, make a dart. But too high a crew or turtleneck and it feels wrong. Thinking about this my jackets (toppers) are also collarless.

I'm 100% v-neck or scoop neck when it comes to almost all tops and sweaters. Like many of the others who've posted, I have somewhat broad shoulders and crewnecks make me feel like a linebacker!

That said, I do own some crew neck tops and even a couple of dresses. If the cut isn't too high on the neck it can work for me. Some crewnecks have just the slightest scoop to them, so I look for those.

I don’t like wider v-necks on me. Partly because I’m always so cold, partly because - like lisap - it feels too sporty or something for me.

ETA: I don’t know - I have a small bust, sloping shoulders, short-waist, medium neck length... I don’t know if the effect has anything to do with these things...

Turtle or mock neck. Even in sleeveless tees. Especially in sleeveless tees. My neck is always cold, even when the rest of me isn't.

If forced to choose between crew and V neck, I'll choose V neck. I don't like the wider V necks on me either, and it can be hard to find them with a shorter, narrower V. At Uniqlo, I can get around that problem by buying a man's V neck sweater in a smaller size, since the V on the man's sweater is shorter and narrower.

I have a average neck length, broad shoulders, small bust, and long waist.

I echo everything Staysfit said -- I share most of the physical traits she lists -- short hair, longish neck, broad/square shoulders, small bust. I like some but not all crews, some but not all v's, some but not all boat-necks, some but not all turtles... It's really very garment-dependent I'd say. I've actually had a very hard time shopping for specific necklines, because that search hardly ever turns up the items that I want. I went on a quest for turtlenecks this winter, and rejected every single one I tried, but it had to do with elements other than the neckline.

I also like Style Fan's point about figuring out which necklines echo the shape of your face/jawline.

I'm under the impression that high crewnecks are somewhat more "current" or in vogue than deep scoops and v's right now, but I deeply dislike crewnecks on myself if they are too high, especially if the t-shirt is very plain and has nothing else to distinguish it. And especially if the fit of the shirt is loose and boxy -- I don't like the feeling that a shirt is attached to me at the neck and just hanging loose everywhere else...

I think I probably look best in a crew neck (long neck, small bust, narrow shoulders), but I feel like crew necks are very boring, so lately I have been trying to limit their addition to my closet. I have been enjoying narrow V necks, halter necks, and turtlenecks, and the occasional scoop neck. I think the reason for my attraction to V necks right now is that I am trying to create a more fluid, flowy style on top, and I feel like V necks create that better than crew necks.

I have medium-length hair that I sometimes wear up, and I find that that works best for the turtleneck tops. I probably look best in the V necks when I have my hair down. I'll have to watch for this in the future and see what variables affect my choice of neckline.

This is something I have been thinking about lately too. I think objectively I look better in a v-neck due to a large and relatively low bustline, but sometimes I just like crewnecks better for the coziness factor. Also in the summer it keeps the sun off my skin. The other issue about it on my mind is that I have sun damage on my décolletage that is just starting to become visible, and I can see the writing is on the wall for when I am older and it becomes more prominent. Probably I will have to make peace with it.

I prefer crew necks by a mile -- as long as they expose my collarbone. The old style one that are almost as high as a mock turtle aren't nearly as flattering, Very few V-necks look good on me despite my short neck, full bust, and long torso. They make my narrowish shoulders look narrower and just make me look dumpy. The *V* in open shirt collars seem to work, maybe because of the added structure. I have a small face, and a lower neckline always makes me feel that showing so much skin throws off the proportions.