I guess it really depends what you want.... You could put a cam and springs in an LS1 for the same money that a stock LS2 will cost you, and end up with heaps more power.
The new generation 6 litre engine is certainly enticing, but it limits tuning possibilities with the E38 and E40 ECU's.
Down the track I think I'll be getting a 6 litre block and adding a stroker crank. Capacity will end up being 427CI which seems to ring a bell for some reason
This will also allow me to keep the Delphi LS1/6 PCM which gives me much greater tuning flexibility.