Now that you know that I shoot Nikon camera with prime lenses, you ought to know what I carry them with.
First things first, I'm gonna talk extensively of the Domke brand here. I'm not affiliated with them or Tiffen (the owner). This is not an ad. I just so happen to have looked at a lot of gear and want to share my thoughts about the stuff I use.
Talking about bags, vests and even straps can seem silly, but it's actually an important part of your gear. A great camera can be useless if you won't take it out because you don't trust your carrying gear.
So, here's what I use for street work : a Domke F-5XZ RuggedWear shoulder bag. It's relatively thin, very tall, water resistant and has a low profile (unlike most Lowepro bags, even if they are well done, I even own two of them). It looks like an old messenger bag, not like a camera bag, and it's not bulky (very handy on the streets!). The F-5XB, its smaller brother can be a nice choice too for rangefinder users. In my bag, I can put : Nikon D90, Nikkor AF 20mm f/2.8D, Nikkor AF 35mm f/2 D, Nikkor AF 50mm f/1.8D, Nikkor AF-S DX 55-200mm VR f/4-5.6, Pelican SD cards case, hoods, Giotto cleaning kit, maps in the back pocket. If I want to take my flash, I take one lens out, that's it.
It's a lot of stuff, and I usually don't take as much with me (I try to restrict myself to 2 lenses per "shooting session"), but the bag can hold it and it doesn't compromise the access. Each lens has its own spot, the camera sits on the bottom of the pads (the advantage of a tall bag, it means that it can hold long lenses too). Nothing bangs anything, it just fits great. Build quality is also great (like most Domke product, it's made in the USA with high standards). Highly recommended.
I also happen to have a Domke Photogs vest. I was actually given to me by a nice and very talented photographer, Mark Tomalty (http://www.marktomalty.com/). It can take all the stuff stated below (but you'll fell insecure with that much stuff on you, be reasonable) and is very comfortable.
It also raises the question: "is it good to actually look like a photographer?". Well, it can be. I think morons will always act like morons, wether you look pro or not, but nice people tend to react well to pro-looking guys. Experience will tell (if you have any, share it!), I haven't try it enough to have a good opinion on the matter. I put gaffer tap on my stuff's branding to keep a low profile, so I tend to contradict myself here... Anyway.
Last but not least: the strap. A nice, robust, made in USA Domke Gripper Strap (the 1" model, the 1.5" is better suited for heavier stuff). It's discreet (again), long enough to put across shoulders, but flexible enough to put around your wrist without a problem. It's leather, nylon and metal, very tough! It beats my Nikon strap by a long shot (same goes for Canon, Pentax or especially Leica straps!).
And you, what do you use and, more importantly, why do you use it? Share that with me!