Awesome. I ordered mine. If nothing else I can hock the book online for an extra discount.
I haven't played the first two, though I wanted to. Think I should play those first? I know there's some continuation of some sort, but I heard it was minor.
You don't need to, and if you get the first two they'd probably take at least a year before you'd even get around to the third. Don't get me wrong, I love the series and it's one of my top 10 DS games - but I think it's a very monotonous, long game that has appeal to a small audience.
I played the first game for almost 7 months before I beat it - some long sessions, some short. When I get a craving for a dungeon crawler EO is where I go, and I finally just opened the second one in the last few weeks and started playing it - I got both games in 2008.
The second one has nicer graphics, they made it harder get overleveled/over supplied (FOEs don't give experience) and I think it's a bit smoother. I don't think the changes are large enough to make it one of those games where you can't play the first after playing the second - so if you order III it'd be easy to go back and play I & II.
If you aren't a *huge* fan of Dungeon Crawlers, I'd recommend diversifying instead of playing 3 dungeon crawlers in one series. DS wise, Shin Megami Tensei: Strange Journey uses the same engine, but is a completely different style of gameplay. Dark Spire has the similar type of gameplay as well, but in my opinion was much harder than EO/Strange Journey. The last mention I'd like to throw out there is Wizardy: The Forsaken Land for PS2. While vastly different from EO/Strange Journey/Dark Spire, it was an awesome game - and if you're new to the modern Dungeon Crawler games I'd highly recommend it.
If you do decide to go for the first Etrian Odyssey, one recommendation (warning - it may be a small spoiler regarding character customization) is to plan your character's skills out early on - ESPECIALLY if you ever want to beat the "bonus bosses" after the main plot. You can do something called "resting" your characters, but in the first it knocks your level down by half I believe? The second is only by 10 levels. This should save you literally 5-6 hours of gameplay - that's how long it took me to "fix" my characters once I noticed bad uses of skill points, wrong characters, and different builds.