Wow.. I can safely say I have not been this excited about the release of D&D books since Christmas 1991 when my parents finally caved in and bought me my first set of books, just after the AD&D 2nd ed revised books where released. (Until then, I had spent 3 years borrowing friends books and such.. not fun).
The Essentials line seems to speak to me for two reasons, one, it is bringing a retro feel back to 4th ed (even more than 4th ed already had), and two, it is the new class structures will make it very easy for me to introduce new players to the game, like my fiance and son. The retro aspect is what I am most excited about, I can see the Essentials line suiting Dragonlance down to the ground. And it may just a small thing, but the re-introduction of class names like the Mage and the Thief, awesome.
Treasure is getting a facelift as well, while I can't say random items is something i am entirely thrilled about, but random item tables do come in very handy in throw together games, or when the players aren't after something specific and DM don't have anything in particular to give out. I do like the control DM's will have over items, the introduction of common, uncommon and rare item will help alot in my games, although it will be they are more likely Uncommon, Rare and Very Rare in my games, as I have always favoured low magic campaigns (Forgotten Realms traditionalists would freak if they saw what I do to the place in my campaigns). I have been houseruling limiting magic items now since 4th ed was released, using other mechanisms to balance the game.
The new campaign settings are something else I am real excited about. I have been a massive Dark Sun fan since it's release (as some people may know, last year I converted every dark sun book to 4th ed for my home campaign - the PDF's are over on ENworld) and Ravenloft has always been another setting I have naturally gravitated towards because I am a huge fan of horror movies, particularly gothic horror. Fear, madness and horror are houserules I have run in my 4th ed campaign since the beginning as well.
So all in all I am very excited about the upcoming releases and cannot wait to get my hands on them. It feels like christmas 1991 all over again.