get D800 or wait... the usual time for Nikon new product announcemt is around august / semptember
so if you can handle this season with your current equipment I'd wait, otherwise go for D800
D3s is a very good body, but full frame with limited crop factor (5mpix images in DX mode) is a little
short even on a 500mm lens
the D800 works as a good FX and DX body in one (16mpix in DX)
the only drawback is that with D800 you get bundle with new memory cards, disk storage and perhaps a new computer

but not for free
