Not knowing your particular situation, it's hard to give the best advice. If you've got lots of experience, perhaps a move to quilts is the way to go. Another option is to get a wide sleeping bag that is used most often entirely open as a quilt, except when the temps are low and close to the bag's limit.
That gives you a quilt feel most of the time, and a tighter mummy bag configuration when really needed due to lower temps.
I love my quilt, but have many bags as well. I'm still trying to learn when each is best used, and the limitations. Mostly my focus now is to determine how light and small a quilt I can use, and have it still accomplish the task for a particular trip given that trip's expected weather.
P.S.—A bag to consider, ranked at the top for value in the most recent "Ultralight Three-Season Down Mummy-Style Sleeping Bags: State of the Market Report 2010" article here on BPL, is the 19 oz. Montbell UL Spiral Down Hugger #3. Currently on sale at MoonTrail for $229. w/ 32 Bonus points good for free gear, it has the "wide" advantage.
http://www.moontrail.com/mont-bell-ul-spiral-down-hugger-3-reg.php If the extra gear for points isn't worth $30 to you, you can get the same bag now at CampSaver for $199.