Backpacker Magazine has their 2012 Gear Review issue out. You can view their ratings for packs, tents, boots, etc. online at ( dead link removed )
If the link doesn't work, go to http://www.backpacker.com
and do a search of '2012 Gear Guide.'
The pack reviews cover 26 pages of products! You can do your shopping in reverse by checking out the reviews/ratings then doing an Internet search on the manufacturer. Most have a list of stores where you can buy their product.
Once you have an idea of the pack you want: (1) See if it is locally available to try on or rent, (2) Double check with the manufacturer's website---you may get a better deal buying direct, (2) Check if it is available via ebay or on a forum website like this one, (3) new gear and/or gently used can be found---lots of people get the notion that they want to get into backpacking, purchase big, then realize sleeping on the ground and getting beat-up on the trail is really not for them----they then have that expensive pack collecting dust in the garage.