Ok, so I’ve ordered Edward Stackpole’s study on Chancellorsville, which was the main subject of this thread. I think I picked it up on Amazon for $5.75. For posterity’s sake I’ll explain why I chose Stackpole’s piece above every other.
It seems that the definitive study on the battle of Chancellorsville is John Bigelow’s The Campaign of Chancellorsville: A strategic and tactical study. Every review I found of this work seems to verify the consensus opinion that this is the definitive study on the subject, though there are two major issues. First and foremost, it was published originally in 1910 with world class maps. It was reprinted by Morningside maybe a few decades ago, also with great maps. That’s where the good news ends, unfortunately every other reprint on the market is far below average in both print quality and maps (most lack maps completely). You can pick a copy up for less then $10, but it seems to be text only and of the lowest quality (many printing mistakes and 0 maps). To compound the issue further, a used copy of the Morningside edition is currently going for $475 on Amazon, and the original 1910 publication is seemingly priceless.
The only other work that I considered purchasing was Sears’ study. I’ve heard some good reviews and the maps appear to be of decent decent quality, but as some one commented above, Sears has his own inherent issues and not everyone will enjoy his point of view (personally I’m no fan of Sears). That said, some people really like Sears and it’s one of the newer works on the subject and you can get a brand new copy for a reasonable price.
Back to Stackpole’s: it’s of the admirable generation of civil war studies that came out around the centennial anniversary of the war, it’s map quality appears to be second only to the Bigelow and Morningside editions stated above, and seems to be well written. It may contain less unfiltered knowledge of the campaign then Bigelow, but it still seems to present its information in a fair and unbiased way (something Sears generally struggles to do, imo).