I have a Big lowepro bag with built in raincoat laptop slot, and can fit my
5D with Grip with 70-200 F2.8 on
24-70 f2.8 lens tucked on side or vise versa,
430ex flash and gary fong lightsphear,
plus my 50mm 1.8 and all my filters, battery chargers,
350d body with grip as well no lens attached. $200
and my god that thing is fckn heavy.

For small day trips i often take my little waste pack can fit 70-200 in there and filters and flash and i carry camera around neck.$50

Lowepro slingshot bag, great for camera body with 24-70 lens flash, and filters , 70-200 in its own bag on my belt. $155

all depends on job/shoot going on. to what bag i take.