I'm patiently waiting for Flight Sim Labs Airbus A320 series to come out.
Once you 'taste' the complexity of the 737 NG, your expectations in FSX will never be the same again.
You won't be disappointed with the FSL (I'm a beta tester for it), so keep waiting

I have the 757 which is fantastic, much better than the Quality Wings one. Also have the C130, a great plane to fly. I bought the 777 on their last 9.99 sale but not flown it at all.
Which one did you not like?
As above, when you've had add-ons to the level of the PMDG, FSL and Majestic, you have a strong feel and desire for deep systems modelling. The CS757 is a half-baked systems modelling - buggy, doesn't work as it should etc etc. Even the engines calculate a takeoff EPR and then never, ever reach it! What's the point? The CS777 also looks equally bad/buggy, judging by a few posts and screenshots in the AVSim forums.
Most add-ons just don't cut the mustard any more.