You'll probably end up happier - and not end up buying several packs before you find one you like - if you stay away from the no-name brands. As others said, get your other gear first, then choose a pack, if possible. However, just to give you some kind of a vague goal, you should be able to do anything you want with a 30-pound load (including food and one or two quarts of water), and a 20-25 pound load isn't unrealistic. You can do this without sacrificing much comfort or convenience; you can also do it with "mainstream" equipment. With a general target weight, you can then start prioritizing gear: if gourmet cooking is important to you, you'll spend more of your weight on food and cookware, and you can sacrifice elsewhere (a tarp instead of a tent, poncho instead of rain suit, or chemical treatment instead of a water purifier.) Also, if you have that target in mind, you don't necessarily have to pass up a sale just because you don't have everything else yet.