any guesses what she is?

I see some Retriever (Golden, Lab or Flat coat) in there and what I've read about her personality seems like it also. I can see Border Collie also. So my guess is Retriever/Border Collie Mix.

could be aussie as much as border collie

Retriever/Collie/Pitbull

Gorgeous dog.  I would venture so far as to suggest there is some German Shepherd far back in there.  Not so much for the body shape, which is clearly some kind of Retriver (IMO), but for the coloring.  Notice the brown highlights behind the ears and on the flanks.  That, to me, suggests some type of marked breed...it's hard to tell from the pictures, but I wonder if she might have a very unnoticeable dark saddle mark...it looks like her shoulders are lighter as well.  I am reminded of Ron's Shadow the Husky/Lab X who is dark like a lab but has faint Husky-like markings like the back stripe.  Not to mention this dog has a rather long muzzle which *could* come from a Shepherd...add prick ears to that profile picture and I'm sure plenty of people would be voting GSD.  I'm sure in a litter of GSD mixes there could be one or two with drop ears.  As mentioned before I definitely see Retriever, though I'm not sure what kind.  I admit I first thought flat coat, but as those are rare I'd be more inclined toward Golden.  The hair on the tail is throwing me for a loop though because it looks like she's got some serious waves in her coat - that is one funky tail!  And long...which I think could be from GSD as well, as well as the holding it lower most of the time part.  I would say GSD/Retriever X with maybe a few other things thrown in there back in the mix.  Possibly Border Collie, though I don't see much in that profile, but the body seems right for that.

I see a whole lot of Border Collie in her,  Thoes staring eyes kinda remind me of one.  Maybe mixed with lab?  Great looking dog!

I'm going to have to go with Lab/Shepherd.  What a stunning dog!

I don't see GSD in this dog, more like Lab and BC, or like someone said Aussie.
 
 

Size-wise, she's right on track with Malcolm and his littermates- they're 6 months old and all right around 50-54 pounds. So collie-sized (22-26" at the shoulder, 55-75 pounds) wouldn't be out of the question as for size.

I immediately thought flat coated retriever from that first shot.  Maybe mixed with some border collie or aussie?

We don't know what our dog, Sasha, is either but she looks exactly like yours. We got her at the end of november - the humane society said she was 2 months and weighed around 7 pounds. Shes almost 5 months now going by the age the shelter gave us. Shes around 30 pounds now. The fur along her back is longer, more wavy and more coarse then the rest of her fur. And the end of her tail has a bit of white as well. Where did you get your dog? Sasha originally is from somewhere in Indiana and came up to the lansing, michigan humane society on a rescue wagon or something like that.

That head on shot looks a lot like my boxer/lab mix (some say pit/lab)

I cant believe how much our dogs look alike.  Our dog Macy was at the North Shore Animal League on Long Island NY.  The people there said she was from Virginia originally. They get dogs from all over the country so maybe they made a mistake.  They must be related---the fur on the back, the coloring, the paws, and the tail are EXACTLY the same.  Even the waves in the fur on her tail are so similar.  Does your dog's fur at the base of her tail on her back stand up when she is excited too?  if they arent related it it some coincidence.

I was seeing either Chessie or Curly coated retriever in both of them.  I like the BC suggestion as well.