I have tons of room still but as of now it's carrying:
Nikon D70  with kit lens
Nikon 70-200mm VR f/2.8
50mm f/1.8
SB-800
misc filters, batteries, lens caps, etc.

The pack has been great for hikes, and the adjustable pack height is  perfect for adjusting the weight onto your hips. It's big enough to  fit the 70-200mm VR f/2.8 and I have tons of room left for future lenses.

thanks to Lee Abraham for pic/comments

Photos contain:
Nikon D100
Nikon 28-70mm f/2.8
Nikon 70-200
Nikon 12-24mm f/4
Nikon 35mm PC
Nikon 2.0x TC
cokin holders
hoya polarizers
lens hoods
Nikon mc-30 cord
RRS 6* rail
tripod wrench
hotshoe spirit level
cleaning supplies
leatherman tool
lens pen, Rocket blower, CF cards
Gitzo 1325 tripod

Thanks to Ernesto Santos for photos

Thanks to Pete (PistolPete) for photos