Speed is what you make of it.
Accuracy is the most important factor by far in any shooting sport.
If you can get the same accuracy with a faster bow/arrow combination then that's a bonus.
But you have to be honest with yourself about how accurate you are with a faster set-up!
I personally like a hunting bow that shoots in the 270 to 280 FPS range for the hunting ranges I encounter where I live. But with the right bow I don't mind 250 to 260 FPS.
Back home where we used to do a lot grainfield edge hunting ,where shots could be a bit longer, I liked something a bit faster...290 to 300 FPS.
Now in the off season, is a different story. <img src=icon_smile_big.gif border=0 align=middle> I like to shoot at higher speeds to push myself to have better form. But come hunting season I throttle 'em back.
If the bow shoots well for you then I don't see any reason to try and bump up the speed. I've hunted with 150 FPS longbows and 300+ FPS Hatchet cam burners. A dead deer is a dead deer.