Well, yeah, that's how it usually works. However, if you built the PC yourself, you should have the original driver discs (motherboard, GPU, etc.) that came with the hardware, in addition to what's on your Windows 7 CD. That way, you can at least run those right after the Windows install.
Barring that, what you can always do is make a list of the hardware (both on the motherboard & separate), then go to the websites & see if they offer stand-alone driver files or if they use a "scan your PC & download the detected hardware" app. For the former, load everything onto a USB stick & pop it in after installing Windows; for the latter, go to the website & run the app to update your drivers.