If you are going to play only classic vertical games, that system is a complete OVERKILL!
It will be generating too much heat and you'd be wasting the power (if there is such a thing).
The reason being that a lot of the new hardware (especially in the MB world) is only enabled via software drivers that are only available for 2000 and XP.
If you run that PC in 98 or DOS, you will not be running at top speed.
If you plan on playing classics only. Put a P3 or older computer in there.
If you need the power, lots of info on the web on how to strip XP (or 2000) to its guts for super fast boot up time!
Good luck!