Add my vote to the "it depends" camp. You just have to try it and hear if it sounds better. To eliminate the cable variable, you can try the bi-wire cables in both single and bi-wire configuration. (For single, connect both leads at the speaker end to one set of posts and use your jumpers.)
If you want to get really finicky, you could run a three-way test: single-wired with supplied jumpers, single-wired with aftermarket jumpers, bi-wired. Not to mention testing to see if your old speaker cables are better or worse than your new bi-wired cables. Hours of fun to be had, if you're really dedicated.
I got better results bi-wiring with one pair of speakers, but better results single-wiring with another.
If you want to get really finicky, you could run a three-way test: single-wired with supplied jumpers, single-wired with aftermarket jumpers, bi-wired. Not to mention testing to see if your old speaker cables are better or worse than your new bi-wired cables. Hours of fun to be had, if you're really dedicated.
I got better results bi-wiring with one pair of speakers, but better results single-wiring with another.