I believe the rumors are that they are planning to rehab/enhance/redo/whatever 5 classic E-ticket attractions for the 50th (7/17/05):
1) Space Mountain (new ride track - possibly Paris version)
2) it's a small world (fiberoptic facade, raised water level -- no more flume, new dolls and effects)
3) Pirates of the Caribbean (new effects?)
4) Haunted Mansion (additional rooms?)
5) Jungle Cruise (new interactive animatronics?)
Of course, these are all subject to budget cuts....
In the meantime, Flik's Fun Fair (DCA) opens this September, Pooh (DL) opens May 2003, Tower of Terror (DCA) opens February 2004. (Note that these are tentative dates.)
Let's cross our fingers that Marty gets what he wants...