I completely agree with a hierarchical approach to Bible study. 

My Bible study workflow has evolved in a rather interesting manner. I used to have a completely print-based workflow, but major portions (all but the commentaries) have gone electronic. It started with Laridian's MyBible on Palm devices and moved to Olive Tree's BibleReader on my iPhone and then iPad. Next came Accordance on my Mac. I now typically read the Bible on my Kindle. It's refreshing, as the Kindle's focus on presenting the text alone makes it easy for me to avoid distractions. 

Here's my current Bible study workflow:

1. I read the passage in my four favorite translations on my Kindle: ESV, NLT, NET, and NIV 2011. Why Kindle? It's easier to focus there than on an iOS device or print study bible. A text-only print bible would be similar, just heavier.

2. I access the ESV and NLT Study Bible notes in BibleReader on my iPad as needed. I also can do Greek and Hebrew research in BibleReader. BR is very good for highly mobile, sophisticated Bible study.

3. I use Accordance on my Mac to do in-depth textual, Greek, and Hebrew research. The ability to compare everything side by side is priceless, as are the Greek and Hebrew resources.

4. My go-to commentaries are the Bible Knowledge Commentary (print and Accordance), the Revised Expositor's Bible Commentary (print), and the Zondervan Illustrated Bible Backgrounds Commentary (print).

5. For more in-depth commentaries, I usually buy them as needed. For basic Bible studies, I usually start with the NIV Application Commentary. The NICNT and NICOT are often my favorite next step.

Why isn't Accordance on the iPad included in my workflow above, especially since I already have it installed? In my humble opinion, it's not quite yet polished enough for effortless use.  I am confident it'll get there; version 1.0 shows great promise.

Why don't I buy my all commentaries electronically? I don't like to read long-form text on LCD displays (i.e. my Mac or iPad), and I prefer the random-access nature of books to the Kindle. I also don't like paying for them twice. Study Bibles work great in iOS; I have a few in BibleReader. I hope to pick up a few for Accordance in a future sale.

PS: Just picked up the JPS Torah commentaries for Accordance (nice sale!) and I must say what a delight it is to read on the iPad. I have the Genesis volume in print, and it's one of my favorite commentaries. It made a very nice transition from print to eBook.

I like to think that accordance is providing a path or bridge for those who do not have theological training in the church to step by step delve deeper into theological discussion.

I also appreciate the available "Legacy" commentaries because they allow us to better understand and access the two thousand years of theology we stand upon today.

-Jon

I would add the NIBC commentary series to your first tier of non-technical, shorter commentaries. I find it very readable and usually helpful for quick information.