If you're not interested in playing games or performing other performance-intensive tasks such as running scientific simulations or designing visual media, I don't see any reason to get a desktop rather than a laptop...
And you don't even need a great one to do any of that either. Video cards are more for processing graphics in real time than for replaying pre-rendered animation or other recorded media. I don't even know if you need anything better than a good-quality integrated graphics chip for what you want.
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