I have ThinkTank Retrospective 30 and it easily holds gripped 7D, speedlite 580 EXII, 70-200 2.8L II, Tamron 24-70 2.8, canon 50 1.4. When you have quite expensive gear (at least for me it is expensive) you need to have well built bag, which you can trust. For me it is important that gear is safe, easily accessible from bag, bag has good and well built straps and you need to change bag every 2-3 years.
Of course, Think Tank Retrospective 30 is expensive, but in my opinion it is really worth that money.