I'm actually looking into doing the same thing. I have a C# book on my ottoman that I've not touched in a while. I haven't had the drive or time to do so. But, i have noticed since I did a lot of web code, a few general principles remain, so I can read and understand what's going on better than the dude down the street who's never seen a line of code. I find Flash was a simple little introduction, but it's very visual oriented, naturally....Something like C# or C++ is a great way to go, and just slowly move with that in some basic forms to get the idea of what you're in for.
C++, C#, Java, Python, and ActionScript are some of the most common and popular forms of programming. I might actually sit down with my Java book sooner or later, granted this java book is up to date. My grandfather lent it to me. Java 2.0, which I hope is up to par.