being the crazy DIY type I've been conteplating wiring up dedicated outlets and switches in my stand (thus negating the need for cord labeling I suppose) and then labeling the switches themselves.... but being the crazy DIY type it's a project that is going to have to wait until I finish at least one of my 3000 others.
I will recommend that if you do use the Ptouch, get the outdoor tape, its only about $2 more and doesnt go all goofball when it gets a drop of water on it! I label each cord at the plug and about halfway up to help when I have to trace something back. I've also got in the habit of labeling my water buckets with the thing so I know what I'm adding / mixing / etc. (helps me keep from adding the 1.014 brackish to my reef or using my dirty water bucket as a new water bucket). I also have my desired water params stuck on the inside of my stand doors and the boxes of spare parts labeled in case I ever have to have a tank sitter!
If your the super anal type you can use the thing to label the breaker panel in the home as well, which sounds like a waste of time but that one time you have a quirk it's well worth it.
all in all the $60 or so you will spend on a p-touch is more than worth it.