Firstly, never use line-level cables as speaker cables. They are not designed the same nor are they rated for the same amps or impedence. They will likely hurt something in your rig.
Line cables expect high impedence & low amps
Speaker cables expect low impedence & high amps
We all know that you aren't supposed to run your head without a cab and that's exactly what could result if you use line-cables vs. speaker cables.
Sure, many have done it and will do it again and nothing will be wrong. But lets be honest, we spend $1,000+ on amps but won't spent an extra $30 to have the right cable?
Now, cables don't buy cables based on price. More expensive does not always mean better, but it usually does.
Things to consider for the cable: soldered connection, insultation, connector. Something to consider is the warranty on the cables. For example, Guitar Center offers a lifetime warranty on Mogami and LiveWire. Just walk in and get a replacement.
Do your research on these and you'll note 2 things about these: 1. they have solid installation, 2. they are fully soldered to their connector not just a point or 2 which is what most cables are.
One thing I've learned is that if you offer a lifetime warranty for a replacement on something that is easily damaged, you are making a good product.
I've been in the studio a few times and have never seen Monster cables. However, I think their newer Pro line will likely be in there. Each studio I've been in has used Mogami. Additionally, for gigging, I was the only member of my last band using LiveWire and Mogami and I was the only one who never had a cable problem.
Take that for what it's worth because I also take better care of my stuff.
The thing is you want quality and warranty with cables and you can get that if you buy the right ones.