I think the ONLY thing you should use in large scripts is OOP. People who suggest otherwise usually don't have much experience. I dislike the fact that some people INSIST on using procedural in large scripts. Prime example: SMF.
If you enjoyed programming like you said, then you should be open to learning as many programming languages that you can. I know that starting out from the scratch with a new programming language can be a pain but it's not impossible.I've been programming in PHP & MySQL for years, but I never got around to learning PHP OOP because I hate learning new programming languages, but I enjoy programming.
Do you think it's worth it to learn OOP? What are some of the benefits of PHP OOP?