Success breeds success. So I think the US market is still the place to be in. And if Europe, Japan and Hong Kong are still falling, why catch a falling knife? Unless you apply Volume spread analysis and see strong buying coming in, I would urge caution when investing in falling markets.
Like you, I see the US markets as over extended relative to other markets and there is value outside of the US but the S&P vs non US markets is just not playing out according to this view... maybe the last few days of correction may just well be the start of a sell off but I am not entirely convinced that the US equity market would fall off the cliff just like that. The surplus liquidity sloshing around would just provide a floor at some stage. Macro wise, the US numbers are holding out well - maybe a bit of slowdown but no where worse than rest of the world. So the liquidity would just be parked within the US markets. And if there is a capitulation, the rest of the world would not escape either and low can go even lower.