Plus, what else is more manly then going through hell, with a chainsaw...killing monsters?
Further adding to the value, you get Xbox Live multiplayer support, while the competitive multiplayer isn't fantastic by any means, the cooperative play is superb, and can add interesting dynamics not intended for the original design (for example having your partner always have the flashlight out, while YOU shoot etc).
Doom 3 ends up being easily one of the best first person shooters in the entire Xbox Library. Plus, what else is more manly then going through hell, with a chainsaw...killing monsters?