Feel free to correct me if I am wrong anyone, but I would say that for a 24' run, you should be looking at a network cable of some sort (MIT or Transparent) since it should be less prone to distance effects (Interference primarily). If I were looking at runs that long though, I would be thinking about monoblocks real quick. A 24' balanced interconnect is going to stand up to that distance a lot better than any sort of speaker cable.
Speaker Cable Recommendation
I have the Krell KAV-500 amp and Dynaudio Contour 3.0 speakers. I'd be interested in hearing anybody's opinion on an excellent 3-figure (new or used) set of cables to connect them. I listen to mostly rock/pop, with a fair amount of Jazz thrown in. Also, the next upgrade is going to be for a beefier two-channel Krell amp if that figures into any recommendation somebody might have.