What type of game are you going to make? Facebook, Mobile (iPhone/iPad, Android, Kindle, etc), Console (PS3/xbox), there's also web based games (usually Flash).
You need a computer that you can use to write the game. Writing code, compiling it or packaging it, etc. For a iOS game, you need a Apple Mac. You also need a $99/year subscription to be an Apple Developer. Xcode (the Software Development Kit for iOS is free from Apple)
If you make a flash based game, you'll need the SDK for that.
You also need a computer for artwork (it could be the same computer as above) and whatever art program you use. Photoshop, Illustrator, etc. I believe Adobe allows you to pay a small monthly fee for using these programs. Previously you had to spend hundreds of dollars to get a software license, now they sell a subscription. An artist will probably want a Wacom or Cintiq for drawing.
Your game probably need to be hosted somewhere, so you'll need some server(s). There are services that you can pay for monthly such as Amazon EC2.
Now is a great time to make games. For like $2k you can get a nice MacBook Pro, pay $100/month to license the software you need, and make a game has unlimited earning potential!