....All the things he said....
It's easy to see that you're very much in love with your WC-setup, but I'd really, REALLY love you to realize that the rig you stated earlier ("I use a 2.2 ghz dual core amd, 3870 vid card") just isn't modern by any means. Reserator doesn't really cut it with current hardware, and to get a passively cooled radiator, it needs to be HUGE.
Now this leads us to the main point, do you, or do you not want to move your rig? I mean ever? If you have all the space you need, sure you can fit a huge rad somewhere, and be happy with the quiet operation. If you want the rad to go along with the case (I guess most do) it WILL need fans. The fans may be quiet, but there are fans nonetheless.
It sure was nice to just slap in a reserator a couple of years ago, to cool the CPU and GPU, but now you'd need a full-cover block on the graphics, likely a block on the NB and another on the regulators. It's just not as straight forward and cheap as it used to be.
Overall I'd say yes, you can get lower temperatures at the same noise level as you would with air cooling. Also yes, you are going to pay more for the cooling. It just all depends on what the user wants and how much he/she's willing to pay and tweak. Just try to see the both sides, while water cooling has its advantages, it IS possible to very quietly cool a rig using air cooling as well.
As for the water wetter.. Well I don't want to even go there. All the hype just makes me wonder how much they are paying you
The 30-50% glycol setups are something I've never ever seen.