Firewall/NAT

After reading a lot about networks and network security, I understand there are some inherent security risks associated with UDP transport. So I thought, no problem I just block UDP transport for ports that don't need it. But that seems to be easier said than done...

Almost every list I see takes the 'just open TCP and UDP for port x' approach. The Wikipedia list of port numbers for example mentions both TCP and UDP for port 80/HTTP, though as far as I know only TCP is actually needed.

So my question is, can somebody  here point me to a more critical list or overview with the absolute minimum firewall exceptions needed for making a certain protocol work? A overview per protocol with info about which transport method is actually used for what and can safely be blocked, would be perfect.

Thanks in advance!