Great board and wanted to say I have learned a lot from reading but have my own questions.
I have just started getting into backpacking/camping. I have only did a couple local hikes but no camping yet.
I plan on just doing little over nights like on weekends. When I have been going out I just put on my hiking boots and grab a bottle of water. I was looking at pack packs and I am a little confused.
I think a day pack with hydration will work but I would want something big enough to put a light weight tent and sleeping bag in plus food, cooking stove ect...I really like the osprey kestrel but not sure what liter size I should start out with?
Will suggest gathering your gear first, leaving pack selection for the last major piece of gear, as total weight and especially volume can vary a lot, depending on what core gear you choose. If the shelter is a small tarp and the bag is a 1# down quilt and the mat is a short NeoAir and the kitchen is a cup and spoon, and you don't pack many clothes, you can use a very small pack, indeed--maybe as small as 35 or 40 liters. As bulk goes up, pack size and complexity follow.
Osprey makes good packs; will suggest the Talon 44 as a starting point--not large, not tiny, not especially heavy while still having a suspension. But you might be able to use something even smaller, depending.
Loc: Gateway to Columbia Gorge
+1 on getting your other gear first. More important than the kind of pack is fit, fit and fit--it must fit your body, fit your gear, and be comfortable for you to carry with your gear inside.
Do note that setting off on a dayhike with only water is not really a great idea. All it takes is one sprained ankle, a sudden weather change, or even a missing trail sign (sometimes vandalism, sometime just an animal scratching too vigorously) and you'll be stuck out overnight. If you are not prepared to be sufficiently warm and dry, although not necessarily comfortable), you may be in dire straits by morning.
Here is an excellent list of hiking essentials that explains why they are needed. They don't have to be either bulky or heavy. Of course when you are backpacking, most of these items are part of your normal overnight gear anyway, and there is no need to carry extra.
The Kestrel 48 is a nice weekend pack; I've used one for exactly that purpose for several years. (Note: as other posters said, the gear you use makes a difference. I use a Carbon Reflex 1 tent, NeoAir All-Season 66" pad, down quilt, and minimalist kitchen.)
My only quibbles were minor: I don't like two-compartment main bags, and I could never get more than about a 5-degree angle on the load lifters. When only carrying 19 pounds for a weekend, neither of those things is a big deal. I also had one big like: the long vertical zippered pockets that held my rain gear perfectly, coupled with the built in rain cover.
While I'd recommend the Kestrel 48 if you can use very light (if not quite ultralight) gear, and travel with minimal gear (no candle lanterns, bigger tents, complete cooksets, etc.), I'd also encourage you to take a look at the Osprey Atmos 50 (the trampoline-suspension equivalent of the Kestrel 48), and the Deuter ACT Lite and ACT Zero packs.
Over Labor Day weekend, my local outfitter (who claims to be my gearaholics sponsor, but I'm starting to get suspicious) managed to fine tune a Deuter ACT Zero 50+15 to fit me. I've always liked the design and build of the the Deuter packs, but hadn't been able to get the load lifters to get more than a zero angle on the load lifters. In the current year version, it appears that the point where the load lifters attach to the pack frame is a bit higher, because I now get about a 30-degree angle on them. (Or else I didn't know how to tweak the fit in last year's model.) I do like the the single compartment design (no zippers to break) and the fact that you can adjust the point where the load lifters meet the shoulder straps; I also like the hipbelt stabilizer straps (not found on the Kestrel.) I'm going to miss the long vertical outside pockets - but if the fit is better, it's a small price to pay.
The ACT Zero 50+15 also has another feature I like: the +15, which is a large extension collar. The Kestrel has a small extension; I could probably fit my winter clothing, or an extra 4 days' food in it, but not both. The Deuter has enough room for both - but when I'm not doing either, it rolls out of the way, and I'm not trying to figure out how to shrink a too-large main pack. (A 65 liter pack, with no extension collar, is hard to use with a 50 liter load.)
I'm not getting rid of my Kestrel 48 anytime soon - but I'm going to give the Deuter another try. (Daisy should chime in soon, probably to give me a hard time about finally seeing the light and going over to a Deuter pack. Or is it you, Mouse? ) The worst that can happen is I revert back to my Kestrel.
Loc: Gateway to Columbia Gorge
Not me; my main criteria for a backpack are: good weight transfer to the hip belt, load lifters to keep the shoulder straps from even touching the tops of my very sensitive shoulders, and weight of the pack itself no more than 2 lbs. YMMV, of course!
May your trails be crooked, winding, lonesome, dangerous, leading to the most amazing view--E. Abbey
Thanks for all the help, I know going off on a hike with only water is a bad idea but I did think what would happen if I sprained an ankle. I did stop by a outfitters and he helped me pick stuff off the shelf that I would buy and use. He said a 50-60L would be perfect.
I did find a pack that fit really good but I didn't think about how it would feel with heavy coat and other layers on.
I should mention I live in Nebraska, yes that's right Nebraska not a lot of places to hike/camp but the few that are around will do fine to hone my skills for out of state and bigger hikes.
We use our Golite 50L packs for trips up to a week or more...but the packs do have some straps that allow you to compress them for a smaller load. And they fit us well, so we sometimes use them instead of a daypack, when we are hiking with a couple of jackets and other stuff...