The have the big write on plastics ones that comes in all sorts of colors.....
But printables all the way.
It's just nice to have a *handheld labelmaker one* that is up to the task.
When I've done that I've always printed off what I wanted it to say, and then fed about the same length out and then wrapped it perpendicular to the cable so that it sticks out like a "flag". This way you're sticking adhesive to adhesive and it's unlikely to come apart/off.
For handheld we use Rhino label printers. They are well worth the marginally more expensive price than cheaper models. They have flag, wrap, and a bunch of other modes.
Absolutely, positively, make sure you get the permanent nylon tapes. It's significantly better than the paper or plastic stuff.
You can also get a desktop Dymo LabelWriter Duo that can print on all the cassettes the Rhino can, which is what we use for larger labels.
█ iCall Carrier Services - Carrier-grade VoIP services from a licensed CLEC - http://carriers.icall.com
█ Domestic termination and origination, toll-free origination, A-Z International termination, dedicated servers, and colocation in our wholly-owned datacenter
█ Real-time ordering via our control panel or XML-based API with over 20,000 numbers in stock