Just FYI, the 2005 and 2006 editions are the same as the 2004 editions.
But the 2006 "limited editions" (September 12 to December 31, 2006) will include both the 2004 editions AND the 1993 "theatrical" (actually home video) cuts, in Dolby 2.0 and non-anamorphic widescreen
. Amazon.com is listing each of the new sets (each is a two disc pack related to each movie) at a price of less than 18$ (plus tax, and with free shipping on orders over 25$).
Edit: Actually there will be extras. Every bonus disc will include an Xbox (only) demo of "LEGO Star Wars II: Original Trilogy" and a trailer for said game. So if you buy all three sets, presumably you'll have three copies of the demo/trailer.
A new DVD set is being RUMORED for May 2007 possibly with new changes to several of the films, but we have really no idea at this point what that exactly entails, beyond CG Yoda in Episode I (though apparently it will be billed as an "ultimate collection" of all six movies).
You can order the bonus DVD (from the 2004 set) seperately, for fairly cheap.
See here: http://www.amazon.com/Star-Wars-Tril...?ie=UTF8&s=dvd
That's all you're really missing by not buying the 2004 set that won't be featured in other sets. Actually, if the prices on Amazon.com are to be believed, you are only paying about $4 more if you bought all three 2 disc Limited Edition packs released this month, instead of the four disc set from two years ago.
Btw, Amazon.com seems to be offering a pretty good deal if you buy all three "Limited Edition" 2006 sets from them, if that is your plan. It's $53.61+tax (free shipping on orders of $25). Much cheaper than ordering them from LucasArts/Lucasfilm, so if you read this in time Cancel your pre-order and switch it to Amazon, you'll have enough cash left over to buy another DVD..