|One of my favorite places|
This tool, as far as I've come across, has the highest quality freely available topo maps on the web. With access to quality raster layers, you can easily scout a route, switching between aerial and topo to get the best sense of the terrain. You can add waypoints, paths, markers, read the slope, get a path elevation profile, and more. You can save maps to your google account, share them, and print them in high quality, true to scale. I found out about HillMap (below) first, but once I found CalTopo I haven't looked back. CalTopo seems to be adding features faster than HillMap these days too. Check out their blog for the latest info.
This web app is great for simple route planning and exploration. It pulls Google's aerial and topo layers, as well as a few other, but it doesn't have the same high quality maps that CalTopo does. You can create waypoints and paths, analyze profile, slope, and a few other neat items. I tend to enjoy HillMap for more general exploration, and switch to CalTopo when I want to create a map I'll print.
Google Maps (figure it out)
While Maps doesn't have the deep feature list that some web mapping applications do, it does tend to load map tiles the fastest on my machines. The Google Maps Labs add-ins also add the ability to pull lat/long coordinates off of the map, measure distances, and create temporary paths. Plus, since both HillMap and CalTopo pull from Google's data, it is worth mentioning.
If you want to learn all there is to know about ultralight backpacking, there's no better source. The archive of articles has a wealth of information that far exceed the cost of membership. Join the forums if you feel like having your gear list picked apart or argue about which brand of cat food can makes the best stove. Generally the forums are some of the most civilized on the internet, and many of the forum regulars are professional guides, adventurers, authors, and seriously experienced outdoorsmen.
Cottage Gear Manufacturers
A year ago, I wouldn't have had a problem with the statement, "REI carries the best available camping and backpacking gear." Today, I'd quickly bring up the cottage gear industry. There's a long list of small companies making high quality outdoor clothing and gear, by hand, in their homes/garages, and selling directly to you. Hikers making gear for hikers - pretty cool. Fair warning, hide your credit card, because you'll want it all.
I'm not going to tell you what each company specializes in because that would ruin the surprise. Also this list is FAR from complete, since I went from memory and my bookmarks, but there's no shortage of other lists and forum posts if you use the google.
AntiGravity Gear, Bushbuddy, Dirty Girl Gaiters, DIY Gear Supply, Elemental Horizons, Enlightened Equipment, Feathered Friends, Gossamer Gear, Hammock Gear, Hennessy Hammock, Hyperlight Mountain Gear, Jacks R Better, Katabatic Gear, Lawson Outdoor Equipment, Light Heart Gear, McHale Packs, Nunatak, Mountain Laurel Designs, PackIt Gourmet, Six Moon Designs, Suluk 46, Tarptent, Ultralight Adventure Equipment, Warbonnet, Western Mountaineering, Zimmerbuilt, ZPacks.
... $500 dollars later, amiright?