While I have the Dake's and several other "study Bibles," I hardly ever look at them anymore. I only liked the Dake's because of the lists that gather related passages together. Those lists were very helpful.
However, personally, I'm not a fan of study Bibles that are filled with doctrinal opinions (even if I agree with them). Most of the time, those opinions aren't presented as opinions but as truths.
Unfortunately, it's becoming difficult to find a study Bible that leaves out the opinions or, at the very least, presents all of the viable opinions on a doctrinal issue. Of the study Bibles, I feel that the Thompson Chain Reference is my favorite. It is simply the linking of passages and references together that makes it so helpful.
Then again, I suppose that the best study Bible is the one that we use to study the Bible.
Lately, my wife and I each prefer just a good, easy-to-read (with clear font) single-column Bible and then use a good concordance and Bible dictionary (either online or in book format). We use highlighters, micron pens and book marks as we go.