Maybe it's not what we become; maybe it's what we are becoming. The fact that Mormonism posits no end to progression and growth - that it really is a never-ending journey and not a destination - really rings true to me.
I can deal with all the inconsistencies and idiosyncrasies (and even absurdities) that exist when humans try to understand what can't be understood, as long as the "grand cosmology" enthralls me - and Mormonism's grand cosmology really does enthrall me. Other Christian theologies just don't do anything for me. Buddhism is the only alternative that I really like, but there are some aspects of Christianity that I love and see as "true" (including the concept of a Savior and Redeemer) that keep me Christian at the core level.
Also, taking almost everything symbolically really helps.