i would go with published order, rather than chronological order.  the first books follow Ender, and the later books are about the other characters back on Earth after the war.

I definitely think published order makes the most sense, but there are really two separate series.  The first is:

1) Ender's Game

2) Speaker for the Dead

3) Xenocide

4) Children of the Mind

That is really a complete series by itself.  The later books are a parallel series, like this:

1) Ender's Game

2) Ender's Shadow

3) Shadow of the Hegemon

4) Shadow Puppets

5) Shadow of the Giant

There are also some short stories, which could pretty much fit in anywhere, as some are prequels and some come in between other stories. 

As long as you read Ender's Game first, I'd just consider the books to be separate series.  I read most of the second, parallel, series before I finished the first, and it doesn't make any difference.

I read all those involving Ender directly first, then moved on to the ones with Bean, Petra, and Ender's brother (was his name Peter? I can't remember). Looks like Matt has the order right (or at least the way I read them).

Thanks for the input! I really appreicate it.

I haven't gotten to the Ender's series yet, but really want to some day.  I 've loved Card's other signature series, the Tales of Alvin Maker, and also read the novel Pastwatch, all of which are really good. 

But, to get to your question, I always recommend reading series in the order the they were written.  When authors write later books that take place in their univere's past, they may be intended to be read first or even as a stand alone story, but I've found that knowing what's already been written adds to the excitement... seeing connections to what we already know about the future, etc.

My favorite example is Asimov's Robot and Foundation (and tangentially Galactic Empire) books.  He initially wrote them as seperate series, then in the mid-80's wrote Robots and Empire and Foundation and Earth, which linked everything together (although not necessarily seemlessly).  Reading that series for the first time in story-chronology-order would have lost the impact those two books had on me as a reader.

I agree with Paul...earlier this year I read Seed to Harvest by Octavia Butler...it is actually a collection of four novels from her Patternist series.  The compilers helpfully arranged the series in chronological order, which is how I read it...but that was a mistake.  The last book in the collection was actually the first written, and when I read it, I realized that the 'prequels' were supposed to help explain in more detail things you were already supposed to know.

However, the two Ender series are so truly unrelated past the first book that it doesn't matter which you read first.

There's a new book in the series coming out soon, Ender in Exile, taking place between Ender's Game and Speaker For the Dead, FYI.

Ender in Exile is already on my wishlist, but I'm not sure I'll wait long enough to get it that way.

I suppose I should have added First Meetings which is a collection of four shorter Ender stories at various time periods, and A War of Gifts which is just one short story published separately (they managed to expand it to over 100 pages with white space, but it's still a short story). 

I just read Ender's Game last spring with my book group - loved it! - but figuring out the book order for this series is such a pretzel! 

After much confusion, I realized it's like visualizing a "V" shape.  Ender's Game is the root of the V, and should be read first.  After that two distinct storylines branch off up the sides of the V and never interesct again, so you can follow either without worrying about encountering spoilers from the other side.  Ender's story continues with Speaker (can't say yet whether new readers might want to consider Ender in Exile the next book -- sounds like it could be if you wanted it to be!), or you can follow some of the other children from the battle school up the right side of the V by reading Ender's Shadow. 

I've been working my way up both sides of the V as I encounter the books.  :P

Has anyone read Ender in Exile yet?  It's good (I just finished reading it), it doesn't really fit into the order rest of the books except it comes after both Ender's Game and Shadow of the Giant (yes, it wraps up loose threads from the latter) and in the afterword Card admits that he had to rewrite the last chapter of Ender's Game in order to not contradict the later books (later additions will have the revised chapter).  As he points out, the last chapter of Ender's Game was always intended to set up Speaker for the Dead, and this new book starts before the last chapter and ends after it.

So basically you can read it whenever you want to read it -- but it fits in nicely after the Shadow books because it wraps up threads concerning some of the Battle School kids.

I never got more than halfway through Xenocide, so I still have that one and Children of the Mind to read.