I have a Camelbak BFM pack,I went on a night hike which it ended up raining cats & dogs, the contents of the pack remained dry, all the compartments on the BFM are zippered. I do have some items in dry bags just in case. Just remember I'm saying in the rain not submerged in water. Also as far as affordable packs go, Military surplus is always cheap esp through this place. http://stores.ebay.com/A-Z-Army-Navy-Military-Surplus which I have purchased from, they are 10 min from me, the link I gave is for their Ebay store, if you look at their auctions on Ebay most of the time things are a little cheaper than in the store. Also Ebay in general sometimes has good deals on packs, I just watched a like new Maxpedition FatBoy go for 43 bucks as opposed to 65 for a new one.

Shadow Out !!!