Wow, you've really got a mix! She's a pretty dog. The spots on her muzzle kind of make me think there might be a little bit of Border Collie in the mix somewhere, but very little judging from how smooth her coat is. The coat is almost smooth-Terrier like, and the eye markings could be from any (or many) of several different breeds.
How big is she, and what kind of personality does she have? Does she exhibit any herding traits?
She's a real beauty, whatever her background, though. If she's yours, I hope you have many years together ahead of you. If you're thinking of adopting her, well, just looking at her, she looks like a good, calm and relaxed dog!