Yes, I don't think you'll be bored by the Head First book we recommended. In fact, I doubt you'll be able to put it down. It's great! Very entertaining and will change the way you think about programming.
Really, though, if you want to grow as a programmer, you should understand the theory and principles of software engineering or your systems won't be very maintainable or robust.
For example, an e-commerce portal I architected was wrestling with the question of dealing with calculating the cost of a delivery when all the items of an order might come from different shippers. They thought of the problem in terms of a giant function which calculated shipping items one by one using a hard-coded algorithm.
The problem with writing a mega-function for the problem is that the code would have been overwhelming to develop (lot's of confusing conditions) and risky to change (because adding conditions/shippers required modifying existing code).
Thinking of the problem in object oriented terms, however, I used a variation of a "chain of responsibility" to elegantly handle the problem. Instead of a single giant function, I wrote a system where you had a chain of components which first analyized whether or not they should handle the item and second calculated the shipping if so. Any unhandled items were passed to the next "link" in the "chain" until all items were handled.
With this system, I organized the code into "links" for each shipper where each "link" required only a few lines of code to write. This completely simplified a relatively complex problem! Additionally, I made the system more flexible and less risky because adding a new shipper "link" involved extending the system instead of modifying its existing parts.
The potential for this sort of elegance in the web space is where ASP.NET really shines over older technologies like ASP or ColdFusion 4 which were more scripting technologies vs. bona fide enterprise software engineering tools.
At the very least, you need to understand object orientation in the context of ASP.NET development, because you need to understand, for example, what the advantages of the MembershipProvider abstraction are, and what you'd need to do as far as subclassing if to add functionality to the out of the box provider or use a database other than SQL Server.
That said, since you're expressing interest in the nuts and bolts of ASP.NET< you may also like this book:
It probably taught me more about the architecture of ASP.NET than any book out there.
MCP, MCTS - .NET Framework 2.0 Web Applications