The LAT(look at that) game is great for training out the reactivity. Control Unleashed by Leslie McDevitt
teaches this and other great exercises.
Have yummy high value treats with you always and when she starts zoning in on whatever, tell her to look at that and then click(or mark it) when she does and treat her. Get her to focus back to you and again mark that, treat or praise. Eventually you can get her to focus back to you without the look at that, therefore redirecting her attention.
Many dogs will react out of fear vs protecting. They have to act big and bad to make the threat go away. Leash reactivity happens because the dog has the fight or flight instinct...leash=no flight so the fight takes over.
Reading body language is important so you can redirect her before she starts the reactivity.
Have your neighbors toss her treats and not make eye contact. Let the dog be the one to do the approaching.
How people approach dogs is important, no crouching or frontal type. They should go sideways and let the dog do the first sniff. Turid Rugaas
has a great short book and a DVD about dog communication. I highly recommend it.
I would get into an obedience class with her and keep her in controlled type situations if you feel you can handle her without her going off. If you can find a class based on the CU book, go for it!