If you want a "headset" go for PC360
If you want a headphone then both AD700x and HD598 would be ideal for positioning and in general FPS gaming.
If your audio card does not have surround sound then there are many external solutions for surround sound.
the AD700x and HD598 do not have strong bass, if you want bass AND good positioning look into DT990 .
there are also many other headphones that are fun(bassy) sounding with good soundstage...
Look at mad lust envy's gaming headphone guide.
I have never had the beats, but many people in here believe the beats are not good for gaming. Many Others think it is garbage.
there are also Sony MA900 , Fidelio X1 and AKG Q701
but DT990 has the greatest bass out of these in my opinion.
Take a look here for review of audiophile headphones that are fit for gaming :
The AD 700 is absolutely AMAZING for gaming. I've heard other members say that some people on the MLG competitions even prefer them over astros. Unless you really need strong bass I wouldn't recommend anything but these for imaging.