i've found that i can do a lot more on a unix or linux box than i can on the same box wi xp pro on it wi afresh install! I kno the programs wor slightly different but u can usually see a difference especially when encoding movies and such. Again i believe it would be down to more effecient code and less module handling which normally blocks up the procesor causing a bottle neck!
I dont do a lot of gaming but from what i've seen Counter strike source is a great online community game! Best fun i've had in ages apart from that others would have to be sonic the hedgehog from the sega mega drive, again GT2-3 gTA or for the PS2 my fav was Metal Gear Solid!That had to top it off!