Headphones

I really like the HD 600 cable specifically, hence I bought a few more of the same cables for the HD 565, HD 58X and HD 660S2. The 600 cable is lighter and less tangle-prone than those (the 58X one is especially bad IMO), the length and 3.5mm termination are perfect for me and the black/red marks are also helpful because of how symmetrical these cans are.

I also like Audio-Technica's cables for the simple reason that you get multiple different cables in the package with one headphone (ATH-M40x comes with 2, M50x and M70x come with 3, MSR7b comes with 2 including a balanced one). They're generally simple and durable similarly to Sennheiser ones.