You can use the benefits of x64 bts OS only if you:
1. Have x64-bits processor (assuming you have one)
2. Every... I
mean really
EVERY hardware installed on you computer has x64-bits driver for your installed x64-bits OS. Otherwise tha device may not work properly and it won't work as expected.
3. Every program you install is recomended to has x64-bits edition (otherwise you can't use more than 3 GB RAM addressing per application because 32-bits limmiting). Especially audio and video programs and raster/vector applications with real-time rendering and so on...
4. If you cover 1-3 you'd better have at least 4 GB of RAM. Otherwise it won't worth it. Recommended is 8, 12 or more for your needs.
5. Money... of course. With money you can purchase even custom 64-bits drivers for any x64-bits OS.