I thought this was an interesting topic, and had to add my opinion...
I'm a vegan actually, which means no meat, eggs, milk, etc. for me. I do it because of animal rights reasons, but I know not everyone here cares about that, so I did just think I'd correct a few errors here.
First of all, calcium from milk is not necessarily the most effective source. In fact, countries that drink significantly less milk, such asian or african countries, and get sometimes less than half the calcium we do, and usually from plant sources, actually have about 1/5 the bone fractures and cases of osteoperosis americans do.
It's also untrue that milk cows WANT to be milked. Think about it, the only reason they produce milk is because they are pregnant, they make exactly enough for their child, and then when the child is mature, they stop. However, the milk industry uses hormones and various chemicals to make the cows produce milk in horribly unhealthy levels. The cows are also kept perpetually pregnant, usually by means of mechanical rape, because no cow naturally produces a dozen calves, one after another.
As far as the taste of soymilk goes, it's definately acquired. It doesn't taste exactly like milk, if that's what you're expecting, you're going to be disappointed. However, it has a very nice taste on its own if you ask me. Also, in terms of cooking, it works exactly like milk, so yes, it's entirely possibly to make milk and egg free cakes, and then you definately don't notice the difference. I actually just had a vegan barbecue a few days ago, and made a few pies and cookies without any animal products, it's not hard at all, and if you think they taste lousy, drop by my house and try a few, I think you'd be surpsied.
All in all, the over abundance of cows really is hurting our environment. Even if you don't care about the lives of the cows, you should realize that it really is hurting you in the end as well. Deforestation, gas production, even world hunger can be attributed to the meat and dairy industry. The majority of the food grown in the United States goes into feeding meat and dairy animals. If the US has a mainly plant based diet, we could have enough to end world hunger. Sadly, most people are more concerned with having their hamburgers and milkshakes than the state of the world in another 50-100 years.