In classifying muscles we usually classify them as Striated(Skeletal,Cardiac) and Non-Striated(Smooth)...

Voluntary vs. involuntary are functional terms rather than morphological terms, and they are somewhat inaccurate. There are a few examples that come to my mind. You can change your heart rate (slowing it or speeding it) by voluntarily thinking about events, yet cardiac muscle is considered involuntary. Another example are the muscles used for breathing, which are striated and you do have voluntary control of these muscles (somewhat) in that you can voluntarily increase or decrease your breathing rate, or even stop breathing temporarily. But in general breathing is involuntary in that you don't have to consciously think about breathing. Also, you can't voluntarily stop breathing indefinitely, eventually you will pass out and start breathing again involuntarily.

From a histological perspective, the muscle in the muscularis externa of the upper third of the esophagus is striated skeletal muscle (although the muscularis mucosae in that region is smooth/involuntary). Other striated skeletal muscles that have no skeletal attachments include the muscles of facial expression and, as already mentioned, the cremaster. Functionally it is voluntary (otherwise you wouldn’t be able to swallow voluntarily. There may be reflex loops that can activate this muscle, as for the patellar reflex, but no one would consider the extensor complex of the thigh an involuntary muscle.).