Don't call something sinful just because it has a few wrong things in it. We need to be careful what we watch yes.
Not to come off wrong but...You said something isn't sinful if there's a few wrong things in it? Elaborate, please. If these things are in any way wrong in the sight of God, is that not technically a defenition of Sin?
As for the idea that we need some kind of entertainment, that's half true. Yes, we need to be occupied or else we will technically waste our God given time here...But it is only from today's modern world that we feel a need for tv and such.
Before there was radio and tv, what did people do? Before telephones, cars, etc. No, these things are not all bad and can be very helpful at times (Tv/radio can be a wonderful witness for God that can reach anywhere in the world). But how useful is simple entertainment, other than occupying one's self for awhile?
In a sense, it can be taking our time for granted. Sure, no one can prove that Jesus never relaxed and enjoyed Himself (in purely Christian ways, of course.

), but do you think He would have been caught wasting precious time here watching a movie or playing a game that does not benifit God? No, He would have spent that time with God in some way. Whether learning, teaching, or helping.
Someone once said to me "Imagine yourself standing infront of God in Heaven and looking back over your life with Him, only to see that 50% of your time was spent doing trivial things rather than Godly things. How would you feel when you have to explain why you weren't doing something productive with the time He was giving you?". Granted, he worded it way better than I just did..but you get the point. In the sceme of things, how 'productive' if secular entertainment?
If you knew you were going to die in 1 week and had the choice of either helping 5 people in a setting that would make your last days very uncomfortable, or going on your dream vacation with all the luxuries..which would you take? instinctivly, we want to take the vacation cause it sounds more fun. Our human selfesh side says "But..but...I'm dying! Can't I enjoy my last time here?". We lose sight on the fact once we're in the new Kingdom that all we'll 'have' is time to enjoy the wonderful blessings of God. While we're on earth, we're on a mission. A short lifetime of work and focus on God seems like an awesome trade off for an eternity of Godly pleasure, eh?
To finish off, I know this is an incredible amount to ask of anyone in a modern day and age. We are so accustomed to our luxury that we see it as neccesity, rather than added frills. Many people still live in the poverty areas that have no reeal forms of entertainment, by our standards. And many of us would go insane in those settings, if against our will.
So, next time you consider going to watch that fun movie or spend hours at a game (Need to practise this one more often, myself) think for a moment if there was something else better you could be doing. Not neccisarily stressful, like work..but something else that's productive. If you don't need physical rest, try some housework while listening to music. Or pick up a book that promotes thoughts towards God, whether Bible or not.

Sure, maybe we all will fall back into some form of selfesh entertainment sometimes, but wouldn't you feel really good to go to bed and say to yourself "Hey, look..I spent an hour of my tv time praying" or "Wow, I got all the chores done! I didn't think I had time to do that today". Wouldn't that feel good?
Sarah