I think everyone's opinion is a valid one, and for me I like the technical critique from other photographers and the honest 'like it or not' reaction from everyone.
That said, after awhile, especially if you are showing lots of images, friends and family can become numb to them, and everything becomes 'good or nice' imho. That happens quicker the less interest they have in photography or images in general.
Occasionally I'm unsure about a crop, a composition choice or new technique and I'll post some images for critique here. And here rather than anywhere else.
I also like posting (what I think are) some of my best images on 500px and seeing the reaction they get, or not,

and while it's starting to become a popularity thing like Flickr, you can't beat letting the people vote, comment, or not,

as way to see what people think of the images.