You'll want a smaller SSD with the larger HDD.
Your SSD will hold your operating system and various other small files / programs.
You can then use your HDD for storage of all data, games, videos, other files etc.
Huge benefit to doing it this way... if you ever have your OS crash, ever need to reformat due to some crazy virus, or whatever else can go wrong - all of your important files will be on a separate drive and remain completely unaffected.
Trust me, that has saved my sanity so many times.
Things can happen, and they find a way to happen. Think of it as not putting all of your eggs in one basket.
Plus that way you get all of the great speed benefits of having the SSD, and the storage benefits of the HDD. It's win/win.