There is no right or wrong when choosing what sort of fabric to work with in an art quilt, the choices and materials are the very essence of your “voice” in your work. But when talking strictly about fabric, there seem to be three primary choices, and they are:
solid fabric:
There are many art quilters who work entirely with solid fabrics–no print, no pattern, no “highs and lows” within the color, like batiks. Many of those who do work only in solid colors find it necessary to dye their own fabric, in order to have a wide range of colors, and more specifically, values in their available choices.

Although the background and hair of this early piece of mine are printed patterns, the face is done in solid fabric. (There are many better examples, but I have a policy not to show other people’s work on my site, as I feel it invades their privacy and control of their own images). A full shot of this piece:

shows that I did, in fact, use hand-dye look alike (commercial) and print fabrics in this piece. This is probably about as close to solid only as I have even gotten in my serious work.
Printed commercial fabric:
If you have ever seen my work, you know this is my very strong bias. I love the layers of complexity that printed fabric can bring to a piece. Plus, part of the joy for me in working with fabric is being able to go into a fabric store and pick out (as I did last week) fifteen different “skin tones” to play with. I cannot imagine coming home with some PFD (prepared for dye) fabric and a few bottles of dye would feel quite as exciting.
The other aspect of working with fabric, at least for me, that gets me inspired and motivated is finding that right piece of fabric for the right place. Not just the right color or value, using an unexpected pattern in a fabric is what I really love to do. I look for fabrics that can be used as lots of “textures” like feathers, leaves, hair, etc. but I also use fabrics in a way that seems unusual, but works.

Look at this piece–at all the unexpected patterns used in the skin and hair, as well as the chair:

Look at all the patterns of fabrics in the hair….

I want you to take particular note of the print in the arm that was a botanical sketch…

and in the chair and the shadows of her shirt, look at the variety of patterns used–from feathery to floral to batik. For me, this is what makes an art quilt more interesting, more exciting, and distinguishes it from works done with paints, or in paper.
Here is another of many examples in my own work of using unexpected patterns and prints:

hand-dyes:
Most art quilters who work primarily in solid fabrics eventually find the need to dye their own. The subtle variety of values in a given color is so limited in the commercial market that the frustration level must be enormous. There are websites that sell solids in value ranges, and that would be a very viable option for those who want to work solid but do not want to dye. I would imagine, however, that the price of these adds up pretty fast. Dying your own, in larger quantities and with more specific control would be the way to go.
The other category of hand dye fabric is often called art fabric. These hand dyes are gorgeous all by themselves. These are just a few from my personal collection:

I am quick to point out that I purchased these gorgeous fabrics from someone else who did the hand dying. The pros and cons of these fabrics is simple–they are so extraordinary by themselves, that they are lost when cut up. Therefore, I have used them as backgrounds, like in this piece:

The hand dye background add a lot to the otherwise dull colors used in the rest of the piece. It was manipulated, however, so that darker areas fell where shadows would be and lighter areas fell where the light source would be. Cutting into one of these fabrics is not easy. It is also not always easy to make them “fit” the area I would want–the orange one in the center of the picture above is still uncut as it just doesn’t seem to fit wherever I have wanted to use it. Obviously, dying the fabric myself would allow me to control the placement of color in the fabric so that this would not be a problem.
I have off and on considered both hand-dying and painting or printing of fabric but have always in the end rejected the notion. First of all, what I love doing is finding the image, finding the right fabric for each segment of the image, and putting the piece together. I do not think I would want to spend so much time making the fabric.
The other reason I have rejected the hand dye route is the chemicals. I gave up commercial photography back in the pre-digital days simply because the darkroom chemicals (after only a few years) were making me sick. I still have allergies and breathing issues that I am convinced stem from the exposure of photo developing chemicals back in my younger days. I just didn’t want to deal with the fumes, the exposure, or even the mess that dying or painting would entail.
In the end the decision you make about what type of fabric to use, and whether or not to “make it” is a function of what you want from the process. It is all part of that word–voice–that I discuss so often. I did a fair amount of both research and contemplation before I decided to stick with commercial fabric and to use pattern with abandon. The decision was part of an ongoing discussion I have with myself about my voice. As my voice always changes, my hesitation to dye fabric may change in the future, as well. But for now, I need to be true to myself.
Be true to yourself and think about what you enjoy and what you ultimately want your work to look like. That will make clear what sort of fabrics you want to use.