One of my favorite study bibles for a number of years has been the MacArthur Study Bible. It has been traditionally available in the NASB and NKJV versions. I have a couple copies of the NKJV version (one I keep at work, one at home). MacArthur's notes are conservative, evangelical, reformed, and aimed at helping the reader understand the passage in a way that is meaningful to personal application rather than a dry, academic approach. Certainly, Dr. MacArthur has the academic credentials to write a set of notes aimed at academics, but he doesn't do that here, and the value of the study notes is exponentially higher to the non-seminary-educated reader.
I got my first ESV bible about 10 years ago, and immediately took a liking to it. Over time, I've come to appreciate the version even more...it is an essentially literal word-for-word translation (it has "all the words", as John Piper spins it). It is written in contemporary English without losing the high nature of certain parts of scripture. In the past couple years, many new versions have become available, such as the comprehensive ESV Study Bible (a great tool, especially if you like carrying around a BIG bible), and the Reformation Study Bible (edited by R. C. Sproul), which is my main carry-to-church-every-Sunday bible.
Now, they are putting the two (ESV and MacArthur) together. The bibles are due out at the end of August, but you can pre-order them from amazon.com, or christianbook.com, where I pre-ordered mine. (I got the brown with woodcut design cover). I'm very excited to get this tool, but it will be interesting trying to decide which one to carry to church (MacArthur or Sproul).