I used FuzzMeasure to set my hi-fi system to iron out some particularly nasty room acoustics in the flat. I tried the free trial first, and quickly plonked down the money for full licence. Basically, this enabled me to use a graphic equaliser to set up a pair of electrostatic loudspeakers (yes, I know, sacrilegious to some) and get the most out of them. Even if you think of this simply as a permanent upgrade to your hi-fi, it's superb value.