(The sun is rising over the Indian Ocean, - must be time to wake up and stare at the wow slider again...)
OK, so this is what we know:
1. The catch-all rule: {margin:7px 0;} is causing the problem
2. The 'problem' is limited to the period of transition between slides, which is handled by the javascript
3. If my count of closing divs is correct, the script is included within this div: <div id="wowslider-container4">...</div>
So, I'd suggest you replace this:
a,blockquote,button,div,dl,form,h1,h2,h3,h4,h5,h6,img,ol,p,table,textarea,ul{margin:7px 0;}
.ws_images {margin: 0 0 0 0;}
.ws_images a ul li img {margin: 0 0 0 0;}
.ws_shadow {margin: 0 0 0 0;}
.ws_bullets {margin: 0 0 0 0;}
with this:
a,blockquote,button,div,dl,form,h1,h2,h3,h4,h5,h6,img,ol,p,table,textarea,ul{margin:7px 0;}
a,blockquote,button,div,dl,form,h1,h2,h3,h4,h5,h6,img,ol,p,table,textarea,ul #wowslider-container4{margin:0 0;}
The logic would be to neutralize all effects of the 'offending margin rule' for everything within the wow-slider container, but leave it intact for everything else on the page...