Oh, duh, I see what you mean. (Sorry, I'm slow today.) You still have to say what you want it to display when it's not the max value. Hm, when I use your formula I get not #VALUE# but FALSE for all the values that aren't Low. What version of Excel are you using?

Regardless of the version, though, you're missing a final argument. The IF function requires three:

1) The condition being tested, in this case E3=1 or E3=MAX(E:E)
2) The value to be used if the condition is true (eg "LOW")
3) The value to be used if the condition is false.

Now, you have two IF functions here. The first one has all three arguments:The condition is E3=1, the "true" value is "LOW" and the "false" value is another IF function. So if E3=1 it displays "LOW"; if it isn't 1, if it's anything else, it displays whatever is the result of the embedded IF function.

The second IF function, however, is incomplete; it has only two arguments:The condition is E3=MAX(E:E), and the "true" value is "HIGH". But you never told it what to display if it isn't the max value. You have to tell it something, like this:What do you want Excel to display there if it's not a high or low value?