Upload & Sell: Off
I wouldn't see the point of doing a private gallery with a limited selection. If you're limiting the selection, ie trying to show the best, I think that is what a blog post is for. I used to use smugmug which as mentioned above is useful for backing up too. But I left them for numerous reasons.
Anyway, I use a private gallery to display all the images. I've had very few people buy a disk from the starting point, so a a gallery is pretty useful for viewing the images.