Since you are connecting your PC directly to your TV, it will be your PC that will be performing upscaling, not your TV, so contents will look just as same as if you have been watching them with your laptop's screen.
With that said, today's monitors and TVs have adequate internal scalers, it should't matter too much.
Btw, downscaling is a lot more merciful than upscaling, so getting a 720P TV and either upscaling low res contents or downscaling 1080p contents are no problem either. You can't go wrong with either resolutions.
...Now if they were classic console games, that's different story.