HDMI is really best for connecting a PC to an HDTV. Consequently, I’d go with a DVI cable. That’ll give you a pure digital signal (VGA is analog) and a much sharper picture at higher resolutions.

HDMI has limitations, though, and isn't always the perfect choice. For example, your TV likely has HDMI 1.4 connections, which max out at 3,820x2,160-pixel resolution at 30 frames per second.

Thunderbolt Gen 1 and 2 don’t support USB 3.1, Type C or even 3.0 for that matter. An adapter wouldn’t have fixed this problem. However, Apple is releasing Thunderbolt 3 later in 2015.