jackryan,
go around and look for speakers and receivers within the Bose' price range. then, play your favorite music and movies through both systems then decide for yourself. if you give us the 15's price, we can perhaps suggest alternative set-ups. this would settle the question on which sounds better. i would wager that for the same money, it won't be difficult to put together a set-up that beats Bose sound quality.
you may have other considerations though. is size of the speakers important to you? i'd like a pair of Dynaudio Evidence or Avant Garde in my room but I doubt if I could even erect those monsters upright in my room.
even if size is of prime importance to you though, similarly-sized speakers like the Boston Acoustics mentioned earlier and even Energy Take 5 or Encore are likely to give better sound.
another possible consideration is the wow factor of a high tech product. if you want high tech, check out the mission x-space system. it uses NXT flat panel speaker technology so you get big sound out of speakers the size of the cover of a lady's shoe box.
if you want to impress people who SEE your speakers, bose will do a fine job among non-enthusiasts (which are the majority BTW). but if you want to impress people who HEAR your speakers, you'll likely be more successful using other (even cheaper) brands.
let us know how your earch goes.