CPU and GPU are the most powerful sources of heat inside a modern computer. There are many different designs of cooling systems for these components. Diversity of solutions is striking. Classifications, descriptions, and comparisons of these coolers lie outside the scope of this article: you may read corresponding sections of popular IT web sites: iXBT.com, Overclockers.ru and others. We are just going to publish general recommendations.
As a rule, a significant limiting factor for choosing coolers for a processor and a video card is your budget: highly efficient and quiet cooling systems are very expensive. What I said in the section about cooling principles means that you'd better use cooling systems with as large heatsinks as possible, preferably made of copper. As copper is too expensive, engineers often use combined solutions: a copper core pressed into an aluminum heatsink; copper contributes to better redistribution of heat. You'd better use low-speed fans in your cooling system: they are less noisy. In order to preserve acceptable performance, engineers use large fans (up to 120 mm). For example, here is CPU cooler Zalman CNPS7700-AlCu:
