I was using a Coleman (2-ton rectangular bag) and my wife had a WalMart bag (what are they? Ozark Trails or something?). I recently upgraded to a new Coleman Ultimate (MUCH better), so my wife will take the old one and my daughter will get the smaller WalMart bag.

I pack depending on the weather, and how much I feel like carrying.

Bags (one of these):
Western Mountaineering Iroquois (38 degrees, down)- I probably use this 70% of the time.
Western Mountaineering Antelope Super Microfiber (5 degrees, down) - My winter bag.
Sierra Designs Wild Bill (20 degrees, synthetic) Only carried if it's going to rain all week, like in the Smokies in springtime.
Eastern Mountain Sports Alpine (40 degrees, synthetic) Same as above, and also used for canoe trips.

Pads (one of these):
Thermarest Pro 4, full length self-inflating pad
Ridgerest Deluxe, full-length foam
Ridgerest shorty, 3/4 length foam

Bivy:
I'll carry an Equinox bivy if I'm sleeping under a tarp or might use a trail shelter along the AT. It obviates the need for a groundcloth, and the breathable fabric does a nice job of adding warmth and keeping off any rain spay if it's really coming down.

My shelter/sleeping bag is a hammock:

Hennessy Hammock
JRB tarp
JRB three season quilts (below hammock & top quilt)

I've never slept better - warm, comfortable, light gear.
My tent is only used now for areas with no trees which is not my typical hike.

I have a picture on WhiteBlaze:
http://whiteblaze.net/forum/vbg/showimage.php?i=12187

Non-winter: a MontBell Ultralight Stretch Down Hugger rated to 32°F or a GoLite Ultra Quilt inside of an ultralight bivy. Use a 2/3 length Thermarest ultralight pad underneath. Total weight just under 2 pounds for the first setup, 2.5 for the second.

Winter: a Western Mountaineering Antelope (-5°F) or Valandre La Fayette (same rating, though I pushed it to -14°F and was still perfectly warm inside a tent), over an Insulmat insultated lightweight inflatable pad topped by 1/4" blue closed cell foam. Total weight under four pounds for everything.

For late spring, summer, and early fall, I have a Western Mountaineering SummerLite +32F down bag. It weighs just over a pound and compresses down to a very small package which is convenient since I can do overnight trips just using a day pack. There are lighter bags, but the SummerLite has a full length zipper, which makes it more flexible. In hot weather, I unzip the bag and use it like a comforter. With the SummerLite, I use a Thermarest ProLite 3 (1" thick) short (short = ~3/4 length). Thermarests are self inflating open cell foam mattresses. I've been using them for about 20 years. I sleep well on the 1.5" thick models, and I'm a side sleeper. I sleep well on the 1.0" thick models if I'm on soft ground. They do take some playing with to get the right air pressure for maximum comfort. The ProLite 3 is very light and compact but does have problems with getting punctured if one sleeps out under the stars with only a light plastic sheet as a ground cloth. No puncture problems when used with a tent or thicker ground cloth. The Prolite 3 is a little thin in terms of padding when sleeping on a hard surface but is quite sufficient on soft ground, pine needles, etc.

For early spring or late fall when things are considerably cooler, I use a Mountain Hardware Phantom 15 +15F down bag. It weighs just under two pounds and compresses down to a relatively small package, although not as small as my Summerlite. Great bag. I've used it for snow camping in good weather. With the Phantom 15, I use a Thermarest ProLite 4 (1.5" thick) regular (regular = full length).

For winter, I use a North Face Snowshoe 0F synthetic bag. The snowshoe does not compress well and weighs just under 3.5 lbs. This bag is a bit of pain since it doesn't compress well which forces me to carry a larger (and therefore heavier) pack, but dang is it warm. I've actually been too hot on many nights when my hiking partners were too cold, and I am not a warm sleeper. With the Snowshoe, I use a Thermarest ProLite 4 regular with a full length Ridgerest (closed cell foam pad) underneath the Thermarest. I sleep well on just a 1.5" Thermarest alone, but when I put a Ridgerest underneath, it's almost as comfortable as my bed at home (although not as wide) .

OK, yep, I've got three bags, not exactly the cheapest way to go. However, I spread the cost out some, buying the first bag in 2000 and the last bag in 2007, and the three bags pretty well cover everything I like to do. I also bought one of the bags off eBay which saved me some $$'s.

HJ

Hello it has been a long time since I have posted("forgive me moderators for i have not...)and hope I can be of service.I have used things from wool blankets and poncho liners to Gov't issue and Wiggy's.The one thing I have learned is get your self off the ground.It is amazing how much a simple 1/2" inch close cell foam pad can make a difference.I don't care what the rating of the sleeping bag is.If you don't insulate yourself from the ground it will draw the heat from your body.I have seen people get almost hypothermic durring summer while using a 32 degree rated Gov.issue sleeping bag.Sure enough they were not using their ground pads.Four inches of debris or a close cell foam pad or a hammock,what ever!Get off the ground.Why do you think modern man(and I use that term loosely)has beds.The"cave man"slept on multiple furs for insulation.As the original post called it,a sleep system is not just a blanket or bag...