good question, depending on month to month situation, some rise faster or vice versa than others. here is a clear answer, and you are a bit slow for not realizing it already COMPARE ALL charts, you will clearly see which index is leading faster up OR down
Depends on your goals/objectives. The ones you mention are stock indexes. The DJIA is a price-weighted index of 30 stocks, the S&P 500 is capitalization-weighted index (of 500 stocks) that "supposedly" is representative of our economy, the NASDAQ is also capitalization-weighted but heavily influenced by technology and biotechnology stocks (traditionally). So the question is, what exposure are you looking for? Also I would add that you want to be careful which specific ETF you invest in. There are a few variants and some are more liquid than others. I would stick with the highly liquid ETFs.
personally, i've gotten better returns (and i prefer) on a longterm basis, the RSP (equal weighted S&P) vs. the SPY (capitalization weighted S&P) do some research. equal weighted is broader in a sense, since the cap weighted is dominated by several larger issues.
Note that the correlation between SPY and DIA is 0.99 over the past 3 years. Maybe this link will help with some trading ideas: http://www.sectorspdr.com/correlation/
DDM for bullish DOW DXD for bearish DOW QQQQ- bullish Naz QID- bearish NAZ Dumping DDM this morning on spike upwards and loading DXD for the fade into aftrenoon and gap down tomorrow morning. Whoopi-freegin doo, DOW shatters all time highs today. The orange ticker at top of CNBC comes up, everyone is saying DOW 14k, blah, blah,..I say retreat to 13,300 by next week. I'll probably be wrong.