I usually like having my comments set to light grey. They are a bit harder to read but my reasoning is that I usually am not reading the comments--I'm focusing on the code. Having the comments light grey lets my eyes go straight to the code even in well/extensively documented code. If/when I need to read the comments I then focus on them, get what I need from them, then get back to the code.

As someone else here mentioned I too like to have my strings set to a very obvious color to:

1.) Help catch mismatched quotes.

2.) Yell out when there's too many strings as a possible early warning that someone's not using enough properties, defined constants, etc.