I just purchased an Onkyo TX-SR601 receiver and a pair of M22ti bookshelf speakers for my medium-sized living room. While I await the arrival of my speakers, I'm considering splurging for one more speaker component, and I'm not sure whether I'll get more immediate use/enjoyment out of a subwoofer, or a center channel speaker. So, I guess my question for all you axiom audiophiles is: if you were building a music/home theater system one component at a time, which speaker would be your next purchase after the M22ti bookshelf beauties? I can only afford to splurge on one component right now, so as between the center (VP150) and the sub (EP175), which will give me more bang for my buck? Thanks!