A while ago I did a post about mech keyboards and how it's important to make a good investment into one. I got motivated to do some articles over all the random equipment that I would have a hard time developing without. One of my most recent purchases was a new mouse mat. I needed to replace one I had been heavily using for two years.
Your mouse pad is a piece of equipment that I bet you don't think about very much. Your mouse pad is just as important as the tires on your car. You can go cheap and get some tires that will wear out fast and require frequent replacement, or you can get a good set that will last a while and provide a smooth ride. A lot of things have changed over the years with mice and monitors that justify a good mouse mat.
When looking for a new mouse pad, you will want to pay close attention to the size of the pad, what material the pad is made out of, and the surface or texture of the top of the pad.
Size
Your average mouse pad is about 10 x 8. I personally recommend 14 x 10. The tiny mats at 10 x 8 were great back in the day when your screen resolution of 800 x 600. My monitors reach almost 5000 pixels wide combined (15" laptop, 24" and 22"). It requires much more space than 10 inches to go across all screens in one swipe. Gamers may want a mouse pad larger than 14 x 10 and many PC game peripheral companies sell giant pads like this. Razer sells an "extended" mouse mat that is large enough for your keyboard and mouse. I first thought that it was a little ridiculous, but I needed a few extra dollars on a purchase to get a bonus on an order and picked one up. I really like it, but it requires a good amount of space.
Material
The material of your mouse pad is just as important as the size and surface. You may not think about it, but hard mouse pads are much smoother to use than soft mouse pads. I've used an aluminum mouse pad before. It's pretty easy to get paranoid about the surface with scratches and liquids leaving rings, but they are really smooth and should last a really long time. They can be pretty expensive to replace though. A great affordable "hard mat" solution is an adhesive skin that can be placed on a multicolored or glass surface.
Surface
Mats use to come in one type when mice were using balls instead of optical lazers. Mat surfaces come in all varieties now. Game companies typically put a lot of focus on this. Razer have speed and control versions of most of their mats. Both seem pretty similar to me. Other companies use a plastic type top for their surface. I'm not super fond of these. Hunt down a bunch of cheap/free mouse pads and find out what you works for you.
What I Use
I use the Razer Goliathus Medium Sized Speed Edition. The mat is great and is affordable enough to replace every year or so if it wears out. The newer version includes woven edges to prevent fraying, which happened to my 2 year old version that didn't include the woven edges. I still use the old one at home. The speed mad uses a tightly woven surface that has a very smooth glide to it. I can push my mouse from one side to the other with just a small push. I'd love to replace it with the Team Liquid version or the Minecraft version, but can't justify it.... yet.