I have personally been using the ESV Study Bible since the day it came out. I’ve never regretted it. It’s notes are clear and helpful, spiritual as well as theological, and it also have loads of really interesting and informative articles chucked in there too, by some of the best theological minds on the planet.
If you have a Kindle, or a device like a smartphone or other tablet, you can now get an electronic edition of the ESV Study Bible for only £9.49! I won’t tell you what I paid for my hard copy when it came out.
Definitely worth your money.