Yeah there are other ways. But are you talking the PC in general or a specific component like your CPU?
Proper airflow in your case is vital for your system's performance and longevity, but the things you need to actively cool are your CPU and (most likely) your video card.
If you're having trouble keeping you CPU cool, we'll need more info: type of CPU and motherboard. In general, I recommend a phase changing heatsink, one that vaporizes a liquid to remove heat from the CPU.
Also, if you feel really ambitious, you can use liquid cooling. Tom's had a pretty big article about that 3Q2005, you can search for it.