The much anticipated ESV Study Bible has arrived (see introductory video below). From my own perusal through it, it seems it will be a tremendously helpful resource for anyone interested in serious study of God's Word. Although not explicitly "Reformed" (such as Ligonier Ministries' The Reformation Study Bible), it will fit well on the shelf of any Reformed believer as it affirms a covenantal understanding of Scripture and the sovereignty of God over all things, including the salvation of men.
For example, the notes on Ephesians 1:4 say:
He chose us in him means that the Father chose Christians in the Son (Christ), and this took place in eternity past, before the foundation of the world. This indicates that for all eternity the Father has had the role of leading and directing among the persons of the Trinity, even though Father, Son, and Holy Spirit are equal in deity and attributes. God's initiative in redeeming the believer from sin and death was not an arbitrary or whimsical decision but something God had planned all along "in Christ." Since God chose his people in his love, they can take no credit for their salvation. God was determined to have them as his own.
You'll find a solid covenantal perspective in the introductory article, Overview of the Bible: A Survey of the History of Salvation, written by Vern S. Poythress.
One other note on the Bible - it's big. Really big. Almost 3,000 pages.
This bible will be a tremendous resource for all Christians and I heartily recommend it.