Storm beat me to it; the Mountainsmith lumbar packs are awesome. While not "tactical looking" enough for some folks, these are the best lumbar packs I've used. They are incredibly rugged, come in great colors, lighter than the tactical nylon stuff, and super comfortable to wear.

The Day model that Storm mentions is the big brother to the Tour model that I wear. By the way, both of those two work with the optional shoulder Strappettes that Mountainsmith makes that let you carry very heavy loads. They also make a line of hydration lumbar packs.

Between my hiiking gear and BOB stuff, we have 6 (!) lumbar packs, 2 duffels, and 2 backpacks from Mountainsmith. I guess you can call me a fan. :-)

Besides, I can wear the Mountainsmith easily in places that tactical nylon gear would get me lots of stares.

Hope this helps,