I'm watching 1165ish on the S&P futures closely today.

Why?  Among other reasons, we're seeing a (somewhat) similar price pattern to January:

1.  Multi-month uptrend
2.  Test of support of a breakout level that met the uptrend line
3.  Several days of choppy price action with closing prices below opening prices.

Here's January (using SPY):



Now here's today (using ES):



If we lose 1165 on ES, and especially 1155, we will change from "uptrend" to "trading range" and it should be easier to sell subsequent rallies.