On rewriting the classics

At the moment, I'm reading Karen Joy Fowler's The Jane Austen Book Club, a novel that intertwines the lives of 6 contemporary characters with the plots of Jane Austen's novels. So far, it's a fun book (more later), but it got me thinking about novels that reference, reimagine or rework classic literature.

Personally, I love intertextality and references to other works, but it does make me feel guilty if I don't know or don't remember the previous works. I've been meaning to read the Thursday Next novels for a while now, but I (shamefully) haven't read Jane Eyre. It's on my bookshelf, but I haven't managed to get around to it.

Usually, a good author will make sure that knowing the reference material enhances the the reading experience but lack of knowing doesn't seriously detract. John Scalzi's Old Man's War is strongly based on Heinlein's Starship Troopers (which I've never read) and yet I found OMW intelligent and engaging and perfectly comprehensible without knowledge of the references. I may someday go back and read Starship Troopers and then reread OMW, but I'm not really in any hurry to do so.

I like that here are people out there writing good books that pay tribute to the stories that they've read in the past. I like that these contemporary works remind me to read the classics because there's a good reason they're classics. I like that a modern twist or revision can make me look at an old favorite in a new light. I just need to do my homework more, so that I'm prepared for the references when they've come. I've read all of Jane Austen's novels and watched the movies inspired by them, and yet I find myself struggling for the details while reading The Jane Austen Book Club - there's a lot I've forgotten since last I revisited Emma and Persuasion particularly (I found myself referencing Clueless instead of Emma for comparison). I want to read Do Androids Dream of Electric Sheep? before I read Scalzi's The Android's Dream, for example. And I want the former fresh in my mind when I read the latter. That's a lot of planning for my reading schedule!

So, what do you think? Do you like postmodern intertextuality? Modernizations of the classics? What are the best and worst that I should read or avoid?