Bug ID

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I've got these critters on the new growth on my (unidentified) green seedless eating grape, they don't seem to be bothering my Cabernet at all however. They are strange little hopper type bugs who move rapidly to the back of the vine they are sitting on no matter where I move to they quickly spin around to the back. Took me a while to notice them because of this, but now that I've seen them, I see them everywhere!!
Plant seems fine, I'm just wondering if they are a big risk or just a nuisance. I've got a few pictures but I'm not sure how good they are for ID. They move really fast, hard to get pictures of.. Also my camera is always focusing on foliage, hope these can be ID by general shape alone...

 

[WVMountaineerJack]

Looks like leaf hoppers, they suck the sap out of the leaves and leave a little drop of dew as a present for you if you disturb them. I have never sprayed for them on anything but a some grape growers spray whenever they see any signs of insect life. Bees can actually gather the dew and make honey from it. WVMJ

 

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So I left these bugs alone, they sure didn't do any noticeable harm. My two little grape vines are full of clusters. I have lots of Cabernet Sauvignon and lots of some seedless green eating grapes. The green ones we will likely eat but what to do with the cab? It's not enough to make wine with, but I figure I could add it to a fruit wine. Any ideas?