I just replaced an old bag, diddn't think it would be a big deal - just skip down to REI, and pick one up..right?-WRONG!
There are so many more choices today,than there were in the "old days" I was lost!

Anyway, my 40 hrs.or so reaserch lead me to a Marmot Helium, which targets your temp. range (15deg.), but if weight is't an issue you could save some $$.