In the photo above are all of the gouges that I regularly use, and a couple that I don't.

On the far right is the gouge I use for rough arching. It's a 30mm #7, mounted on a handle that I turned for it. Notice the two raised handstops on the handle, and the large knob on the end. The second tool over from that, the one that looks like a spoon, is what's commonly sold as a "violin arching gouge". It doesn't work, and you don't need one. The worst thing about it is that it lowers your attack at the wood so that it's very easy to bang your knuckles against the sharp edges of the wood and cut them. The only use I've found for it is cutting down soundpost patches.

Japan Woodworker sells both types, as violin arching gouges, but it appears from their catalogue that the one that resembles mine has a flatter gouge, which is not a good thing. The very long gouge under the others across the back is my original arching gouge. Even though it's much larger, it doesn't work well because it's flatter. It removes too much wood at once, and takes a lot more work. It's not as versatile, either, and I haven't used it in years.

Also in the right grouping are the four chisels and gouges I use the most. The first is a 7mm chisel that's handy for small jobs, but not used too often. Next is a 1/2" chisel that I use for necksets. There aren't really too many chisel jobs, so these two are adequate. Next is a 3/4 #9 gouge (I think--I ground off the number, thinning it). I use it mainly for edgework and for the undersides of fingerboards. The flat gouge that's second from the right is a 25mm #3, and it's the one I use the most, for smoothing the arching, and rough graduation.

The gouges on the left are what I use for scroll carving. They were made from light-duty carving gouges, by thinning them on a belt sander, and cutting off half the handles. From left are a 12mm #5, 7mm #8, 5mm #7, and an unusual round in-cannel (bevel on the inside) gouge that's only used to drill out the inside of pegboxes. By borrowing someone else's couplete regulation German scroll gouge kit for a few months, and seeing what I actually used, I decided that these were the only ones I really needed.

Finally, between the two sets, in the front, is a knife blank that I sharpened on the end with a curved edge. If you use it flat side down, it cuts flat, but bevel side down it acts like a very flat gouge. I use this for a number of things, but it's most useful on scrolls.

Notice how all of the gouges are sharpened. The edges aren't straight, as on the chisels. They're shaped more like a fingernail. This is not how carving books tell you to sharpen gouges (which is either straight across, or with the corners out ahead of the rest), but woodcarvers work slightly differently from violin makers, and need something different.