I find the physical aspects of the church reassuring. It reminds us that we are dealing with a God who has experienced blood, sweat, dust, and tears. Moreso, it reminds us that we have a God who takes these things and uses them. One of the more profound scriptures (to my understanding) is found in Moses chapter 6:59-60:
59 That by reason of transgression cometh the fall, which fall bringeth death, and inasmuch as ye were born into the world by water, and blood, and the spirit, which I have made, and so became of dust a living soul, even so ye must be born again into the kingdom of heaven, of water, and of the Spirit, and be cleansed by blood, even the blood of mine Only Begotten; that ye might be sanctified from all sin, and enjoy the words of eternal life in this world, and eternal life in the world to come, even immortal glory;
60 For by the water ye keep the commandment; by the Spirit ye are justified, and by the blood ye are sanctified;
Why is this a powerful scripture for me? To be honest, I don't entirely know. But I know that it has something to do with the manner in which it combines the physical and the spiritual into an explanation of at least two acts wherein the temporal and eternals planes connect.
One of these acts is baptism, a form of which is practiced in the temples. For some reason, whether or not we enter a pool of water in a certain way at a certain time has some effect on our eternal standing. It is a completely arbitrary standard, a symbol made important by its importance, not for its ability to explain anything. It is such an odd little thing for the living, one wonders why people balk at doing it for the dead.
The biggest question regarding baptism for the dead is the issue of free will. Mormons cheat when they answer this. They say that acceptance of the gospel is entirely up to the dead person. While this may be technically true, I am not sure that Mormons believe that the dead will reject the offered ordinance. We assume that they will have some sort of knowledge that will make it clear to them what to do. This may or may not be true (our ignorance of the afterlife is far exceeded by our ability to discuss it). In any case, this is what appears to be driving the persistent baptisms for holocaust victims, Adolf Hitler, and Elvis. I believe the idea is that it costs nothing to the person doing the genealogy work to be baptized and it may help those poor departed souls. Any activity that allows us to pat ourselves on the back, especially while ignoring the offended cries of the ignorant gentiles who don't really understand what we are trying to do, makes me suspicious. I do not mean to say that temple work is bad or inherently prideful (I believe the exact opposite of that actually). Rather, I worry about the pride inherent in using the gifts, ordinances, and houses of God in a way that seems designed to hurt others (especially when the Brethren have asked us to stop).
All temple work (all ordinances, really) are a sublime combination of the earthly and the heavenly for me and I love them for it. Ritual and Mystery cause me to rely less on my own understanding and more on God's. I don't believe that to ever be a bad thing.