It's a bit of a challenge right now to find suitable necklines, as it seems the pullover trend has overwhelmed the market with crew necks. But some crew necks can still work -- I look for versions with a bit of a scoop (i.e., either a low crew neck or a high scoop neck). And also boat necks, surprisingly, can be your friend. I think because it exposes collar bone, but also there's something nice about how boat necks drape.
I have the added challenge of really needing a petite, as I'm only 5'0 tall, but here are some basic tops that have worked for me lately:
Jcrew vintage tees:
I just ordered more today. I am hoping they are same cut & fabric as the ones I bought last year. This is a casual tee, I wouldn't wear to work, but it's great alone or for layering. I have the V-neck and the crew, which is has that magical "not quite crew, not quite a scoop" neckline. For me, these fit fluid/relaxed/ever-so-baggy without being too baggy. Not body con. They work great with skinnies and boyfriend jeans, tucked in or half tucked.
https://www.jcrew.com/womens_c...../24500.jsp
and
https://www.jcrew.com/womens_c...../36183.jsp
This V neck sweater from BR fits nicely if you are aiming for fluid relaxed fit; I just warn you that the quality isn't that great, unfortunately. I bought one last fall and it's already pilling quite a bit:
http://bananarepublic.gap.com/.....=689271002
If you want something more body-con, I tried this on -- didn't buy it. Nearly bought it...
http://bananarepublic.gap.com/.....=933039002
I wrote a recent rave for this camp shirt:
http://www.anntaylor.com/silk-.....010&p
Yes it has a collar. But it still works. I wouldn't button it up at the neck, like shown in the picture. And, I don't agree with the recommendation to try collarless shirts -- I find these look absolutely horrible on me. I'd rather have a collar that doesn't stick up on the neck, but rather, lies flat, and when open at the neck creates a V. Collarless shirts don't usually do that.
This sweater works surprisingly well, I think because the fabric is so drapey, and it's nearly a boatneck. And yeah, it's striped. Go figure.
http://www.anntaylor.com/marin.....tid=cata00
This is pretty cute:
http://www.anntaylor.com/woven.....038;catid=