I've been a few questions about materials which I am delighted to answer.
I use only Heavy Body Acrylics by Liquitex on 3/16" Fiberboard Panel. Many places carry fiberboard, I've been getting it from www.fineartstore.com. I think this kind of panel is the best because the surface is smooth, and the paint slides around because it doesn't dry too quickly. It's also really inexpensive and comes in a variety of sizes. I prime the surface with acrylic paint only. . . usually a ground color of red.
I prefer a disposable palette because I like tossing the colors I mixed at the end of that day and moving on to a whole new set of possibilities. I felt keeping the same palette was forcing me to use the same colors over and over.
I really wasn't happy with acrylics until I discovered the above - another panel I like to use on occasion is by Raymar, their linen one - it has a canvas texture, so it's totally different, but it too has a good surface for acrylics.