Pyromaniacal said:
People seem to view it [video gaming] as more of time killer if anything.
Here is my way of viewing things:
hobby - something you do in your spare time because you want to do it, and don't need to do it to survive
Examples
playing video games
raising children
sports
time waster/time killer - something you do to pass the time when you can't do a hobby.
Example
playing Angry Birds
only on the subway ride to/from work
The main distinction is whether or not you would do something else given the opportunity.
As a bonus here is my definition of hardcore gamer:
hardcore gamer a person whose primary hobby is playing video games