I have used the Hilleberg Nammatj 3 the last two years, it replaced my TNF VE-25. It is a superb, light weight 3 person with a great vestibule area. I have stayed dry in it in all conditions. I just got back from Ekwok on the 31st after nine days on the Kokwok. My only complaint is that it does get a lot of condensation on the inside of the tent but not the sleeping area. I got my at BArneys and they matched a great price I found in Seattle.
The Nammajti 3 weighs over 6 and up to over 8 lbs depending on model. The lightest model Hilleberg makes is the Rajd (pronounced "Ride") at 2lb 2oz with out poles, which looks more like a reasonable backpacking option (http://www.hilleberg.com/Catalog/tents_47616_products.htm).
You may also want to have a look at the Tarptent by Henry Shires (http://www.tarptent.com/). Two of my hunting partners just picked up Tarptents on eBay for around 150.00 each (one got a Squall 2 and one got a Cloudburst) These look like great backpacking options as well, check them out.
