No. In fact, you have some control over this. The two major factors are how many fans you buy and install (usually set by how much heat / power your system components use), and which fan designs you buy. In choosing fans, read carefully the sound ratings of each versus the air movement capacity (usually as CFM for a given motor speed) and, if available, user reviews / reports of noise. You can buy fans that are noticeably quieter than average but still move a lot of air, although you may find that the netter quieter ones are more expensive than the cheap ones.
I also MUCH prefer to buy fans with ball bearings (preferably, "both" or "all") rather than sleeve bearings - they last a lot longer ans stay quiet.
The last machine I built used Noctua fans and they are very quiet, although some claim they are over-priced. The machine I'm using right now has good-quality fans that were supplied with the case (an Antec Sonata II) and they are fine for my use. For the CPU I have a Zalman cooler and fan.