Assuming you will only be doing day hikes out of a main camp...
-Water filtration: I'd go for a base camp purifier like http://www.rei.com/product/737349/katadyn-base-camp-water-filter, and just fill bottles from that; hand pump filters also are good but require more work on your part.
-Tent: Check out http://www.steepandcheap.com. They offer a new deal every 20 minutes or so, and they put up at least one backpacking tent a day I've noticed, at really great prices
-Ultralight Stove: I wouldn't skimp on this. Try and get a nicer one if you can. MSR makes some pretty good stoves. Unless you can make a fire...then just bring that old cast iron frypan
-Packs: Check out Osprey Packs or Gregory. Both great quality and pretty light if that's what you're looking for. Expensive so buy them on sale. Some good packs are offered on steepandcheap.com from time to time.
-Bags: (sleeping bags). There are so many out there, just find the right temperature rating and decide between synthetic or goose down (ongoing debate). Just remember, the smaller/lighter you go at a fixed temp. rating, the more you will pay.
-If you plan on getting lots of snow, good snowshoes will be a necessity. I'd recommend MSR again http://www.ems.com/product/index.jsp?productId=4085830&cp=3712723.3718184
and a tad lighter but real pricey http://www.ems.com/product/index.jsp?productId=4082823&cp=3712723.3718184
-sleeping pads: sleeping pads? rocks will work.
