Ok, It's hard to get excited about planning this far in advance, especially since I've got another cruise and probably two trips to WDW before Oct 2009 but you have to start some time...
Who's gone on the Eastern before and what are the can't miss excursions?
St. John and especially Trunk Bay are just beautiful. I will post some pictures up in the first post soon.
If you want to stay on St. Thomas, go to Meghan's Bay (suppose to be one of the top 10 beaches in the world - I prefer Trunk though).
Also on St. Thomas, you can take an island tour and go to Mountain Top. There are also the cable cars right near the pier. From both you'll get great views of the bay. Again, I have pictures of this I can post as well.
On St. Maarten, we did the "under two flags" tour. You get to see both sides of the island (french and dutch). We then went to the beach right in town. On our second cruise there, we went to Orient Beach. I think it was over rated. Very rough surf too. Next time we are going to go over to Maho Beach. Not for the beach as much as the excitement. I'll have to post a couple of You Tube videos to show what I mean.
Hope that helps.