Buried in the above responses are many answers, some conflicting.
The answer to remember is that it "depends"...
Each company determines what is acceptable, not only for plebes, but also for upper class cadets.
My 2014 cadet did have two monitors for a time - the issued one, as well as a larger one that was added sometime during the year. Later in his plebe year his company decided that plebes could only have one monitor. He ended up selling his issued LCD monitor, keeping the larger one. As a yuk, his company still limits the cadets to one monitor.
He also has an Xbox, playing it occasionally on weekends. At other times, it is locked inside his bureau closet. While he does have another computer at home, he said it was not worth the hassle bringing it to West Point. As for network access, a cadet cannot connect a personal computer, router, or game system to the government network. For Xbox updates, he uses the hotspot function of his android phone; latency prevents its usefulness for multi-player gaming over the internet.
For a printer, he replaced his issued printer with a color laser printer. The issued printer had expensive ink/toner cartridges; the laser printer was more economical for supplies.
Regarding Netflix - it is a popular pastime. Again, use varies company-by-company. At one time, it was possible to view movies during ESP (Evening Study Period) while doing homework or after it was completed. Again, for his company, this has changed; Netflix viewing is now prohibited during ESP. This use to be a popular pastime during Q duty. Again, no longer permitted in son's company.
In general, best advise for incoming new cadets, follow the guidance you get from West Point, and from your assigned team leader. Advice here on the forum is not the official word.
Will you have time to view movies or play video games during your plebe year? Perhaps...but it will be a privilege, not a right. And each company will determine what privileges you will be granted. Should you play video games or view movies? Perhaps...again after you make sure you have done your best with all your academic, military, and physical requirements, and after your company has granted that privilege.