Not a big fan of passive cooling solutions myself, these require a lot of surface area to give away heat and usually the operating temperatures remain higher than I would ideally want them to be...
For a regular PC with an average or low-end hardware and no gaming GPU there is not much point in going for water cooling setup, you can find good silent coolers. If you are building a high-power system for gaming or for work however going for water cooling can help you make it silent even under constant heavy load. Water cooling is also very helpful when overclocking the CPU or the video card as you can generally squeeze more performance without getting too high operating temperatures.