Edited 1-11-07 Without a doubt, my Tamiya 1/350 Bismarck with all 3 PE detail sets from White Ensign Models. This is a project that I'm really looking forward too, and also dreading at the same time. It's going to go on a shelf just above the 50" Plasma TV in the family room and will be a centerpiece for my collection. My skills aren't where they need to be yet, so it will be a while before I build it, but I look at the full blown Bismarck build as being my "Holy Grail" so to speak.
Hmmm... I would have to say probably the latest few Dragon 1/35 armor aquisitions in my stash, which would include
Nashorn
PzKpfw IV Ausf D
M4A1
M4A3
M4A3E8
I'm trying to get my armor building, painting and weathing skills up on my simpler kits before I even think about touching those. LOL
My Pro Modeler Ju88C-6 and Stuka get honorable mention....