To be quite honest, all of them are as available as the others. The top end monitors for 2K and 4K monitors, have DP (Display Port, which allows up to 4K) and HDMI which in some cases allow 2K as well as DVI. VGA is more for 1280x720 and 1920x1080 Monitors, but they tend to have HDMI and DVI too.
In the future, in my opinion, VGA is going to slowly die out, and Display Port will be used much more commonly.