Don't just settle for any sleeping bag
Specialty retail is serving tall and big men and women with sleeping bags that fit!
As a young man backpacking with my friends, I remember having to pack a small sheet with my sleeping bag. I had to use this sheet to help cover my neck and head at night because my sleeping bag wasn't long enough to cover my 6'5" frame. It worked pretty well back then and you won't hear me complain about my small bag days. I barely had enough money to buy a bag in the first place!
Things have changed and a few retailers offer longer sized sleeping bags for tall and big individuals. The majority of sleeping bags out there are very good quality, but when it comes to sleeping overnight in the mountains, the bag fit is very, very important. GargantuanGear.com is an on-line tall and big outdoor retailer that offers several tall bags that range from plush car camping type models to lean and light backpacking bags in lengths up to 100" (that's fits up to 7'!).
Temperature ratings are also important, not just size, when it comes to finding the right bag. You can find cold weather bags rated down to -50 if you search long enough, but the sweet spot for most recreational campers is -5 to 15 degree ratings. I use a -5 degree bag that fits my now 6'7" height (I kept growing after high school). It's well made, super comfortable, and my neck and head are warm minus the sheet-something I am still getting used to! I prefer cold rated bags because I often camp late into the season when temperatures are well below freezing, but when the colors are spectacular!
For the bigger individual, wider bags are also important so that the feel and fit isn't too restrictive. One drawback to larger bags, especially ones approaching 100" in length, is that they are larger and require bigger stuff sacks making them almost impossible to carry on a backpack. If you need a small stuff sack size, you can find down bags that compress to acceptable sizes for those long backpacking trips. Having survived the pain of using gear and equipment that was too small, its good to know that taller and bigger outdoor gear items are available, especially sleeping bags.