There are a number of plotters that come with thier own software. Some are pretty good,others are so so. The Roland comes with Cut Studio. At first glance you get the impression that it's just ok,nothing to elaborate. But once you get into it and start to use it you'll realize,hey this is pretty cool. There are many many features that are within the actual CD,but not listed in the manual itself. One really nice thing is that there is a plug in within Cut Studio that will allow you to use Corel or Adobe Illustrator to vector your images. It sort of links the software programs together. You can resize them,stretch and skew them to. Then just hit the cut button from within Corel or Illustrator. Then stand back and watch it go. Pretty cool. What it does is send what ever you are cutting,to Cut Studio for the actual cutting. But you manulipulate your images within one of the other two programs. or you can use it by itself. Some of the off shore plotters do come with software,but they are just ok. One thing you have to remember that these machines are precision, so in essence you get what you pay for. These off shore machines lack parts and service big time. But for the guy that uses it once in a while you'll probably be ok,untill it craps out. But they will not survive continual shop use or a trade show gig. So just beware and do your reasearch. As for some of the software programs out there you can spend big big dollars for them. For the professional sign guy, yeah I can see it, and the learning curve is not easy. But for what we do, skulls, flames,tribals, paint masks and the odd stencil etc,you don't need to spend a grand on software. Spend it on the actual cutter/plotter. There are some really good plotters out there, Roland,Graph Teck,and Summa,just to name a couple. Parts and service are readilly available so there are no worries there. Once the word gets out you have this thing it will pay for itself in no time. They are great time savers, less time with a roll of masking tape in your hand laying out a flame design, and they really excell at lettering. Just do some 1/8 inch letting with an xacto blade and you'll be ready for some therapy. I wouldn't want to be with out one. Besides it will broaden what you can accomplish as a custom painter/artist. Jeez,that was a long winded answer.
My preference for the creation side of things is Adobe Illustrator.
While some plotters come with software for creating or "vectorizing" artwork, I've found that they tend to do sloppy work in their creation and they tend to have WAY too many anchor points/nodes in the finished product. By me drawing the artwork myself I get the artwork I need in a format I can use, it cuts faster and smoother than the auto-traced stuff and I know what I'll get as an end result.
Yes, I can use an auto trace program and then try to clean it up, but to be honest, it takes less time to draw it right in the first place.
It also lets me save or export the finished artwork in a wide variety of file formats for print or for cutting in the future.