I'm a bit of fan of lumbar packs for outdoors activities (although not so much for urban wear). I've got a bunch of them ranging in size from the Mountainsmith Vibe II (pretty small) to a Mountainsmith Tour (pretty large). I've also got two True North Gear packs, a SERAC SAR and a Double Diamond. The TNG packs and the Tour are all very large lumbar packs that have good compression straps as well as shoulder straps that work great when the load out is on the heavy side. They're nice for warmer weather IMO since they don't make my back sweaty like a backpack, so they're great for day hikes.

The only time I like the dreaded 'fanny pack' for urban wear is on the rare occasion that I want to make a quick late night run to the store or for wearing to the gym. I can get my wallet, keys and my Ruger LCRx .38 Special and one speed strip into the Vibe II; that makes it great for when I'm wearing sweats and don't have pockets yet still want to have my wallet and a sidearm.