The above setting you mentioned turns off vibration for all applications.
However depending on which keyboard you are actually using, you can turn the vibration off just for the keyboard press and leave other things unaffected. SGS2 comes with at least 2 keyboards. The Samsung keyboard and Swype keyboard. The Samsung keyboard has several flavours buried with in it by the way incl. 3x4(T9) keyboard, and 2 handwriting recognition box that I kind of like actually where you actually write with your finger and the text is produced (powered by DioPen)!
Anyway if you are using the swype keyboard as most people do, in the settings screen a little way down is "Vibrate on keypress" that you can turn off - which leaves it on for every other application.
I am loving TSwipe keyboard by the way Swype cabable + Asian language + toggle capitisation of any word + fully customs colours and layouts + single line scrolling word suggest + phrase suggest + Web keyboard (input from PC keyboard on the same network using a browser dialog box) + instant sentence + math symobols + smilys etc etc....