1. Games: Generally if you are a hardcore gamer stick to windows, its what the games are written for and work best on. Not saying you can't play games in linux, however selection is limited, and it dosn't always work right (getting it to work is sometimes more fun than playing it)
2. Virus software: Awhile ago I heard someone mention there was actually virus protection software for linux. Personally I have never seen said beast in the wild, nor have the foggiest idea what it would be good for. Generally Linux is not as suceptable<sp?> to viri, no activeX to exploit after all (the script kiddies are crying in their pillows at night); and when you do get hit, due to the unix security model damage is limited since you don't have permission to format the hard drive, or do other nefarious activities.
3. DVD Burner: I'm pretty sure this is supported, but I don't have one so I can't say how well.
4. etc: browse internet, read email, do word processing; check.
Basically its not quite an end user system as windows is. You have to know a bit about how it works. However on the plus side since you actually know how it works when something goes wrong it is alot easier to fix. No reboot and hope its fixed (seldom works anyway in linux)