Hi goddess! So, they are still at it huh! So sad to get neighbors like that.
I agree with Pam, there are many fast growing privacy plants you can plant all along the fence. If you don't want flowering vines I would go with some Italian cypress shrubs that you can trim to any height and width you like. Planting them close together all in a row will make them grow together and toping them will make the bush out faster. I planted some 2 feet high all along the side of my last home that faced my nasty neighbors junky messy carport. They were on sale in Home Depot and I bought 10, in no time at all they were 5 foot high and acted like a living fence.
All about Italian cypress: http://www.fast-growing-trees.com/ItalianCypress.htm
All about Privacy Plants:
http://www.ehow.com/about_4595876_privacy-plants.html
Pam's idea of bougainvillea is great hung on some trellises. Just be aware if you plant these that do have huge sharp thorns and if you don't keep them trimmed they can take over your whole side yard in no time at all as they are very invasive plants.
You could also go with some pretty privacy screening between the yards as there are many outdoor types. If Hubby is handy you could even build a nice one with planters at the bottom. Like these:
http://www.solutions.com/jump.jsp?itemType=PRODUCT&itemID=1552
http://www.luxuryhousingtrends.com/archive/2008/04/wooden-privacy/
http://green-fab.com/blog/2008/03/30/site-design-a-personal-work-in-progress/
http://www.ehow.com/how-does_4579867_outdoor-privacy-screen-work.html
This site is a little slow but good:
http://www.woodworkersworkshop.com/resources/index.php?search=privacy%20screen
http://www.betterimprovement.com/resin-outdoor-privacy-screen/
http://www.buzzle.com/articles/outdoor-privacy-screens.html
Or a inexpensive one with bamboo:
http://www.improvementscatalog.com/home/improvements/792928619-slatted-bamboo-privacy-screen.html
So sorry you have to go through this, but if it really bothers you then I would take the matter into your own hands.
Good luck and we would love to know what you decide to do.