Things didn't go as sequentially as these posts make it seem. I was popping back and forth between the various 'flavors', and it became clear as I would use one for awhile, then try another, and so on, that
Object Art's Dolphin XP was the best match for my preferences and what I'm looking to do. Like MT, it's focused on the Windows platform, and provides facilities to smooth working with DirectX and other MS APIs, but maintains a more consistently 'Smalltalk' rather than C++ feel while doing it. Given that one of my goals is learning Smalltalk and the Smalltalk-way of doing things as much as the actual creation of a game, that was a definite plus for my purposes.
It's not perfect (at the time of this post, the help system is one version behind the release, and is a separate install), but it's got many strengths that tie in to what I'm looking for in my environment of choice. It's got a friendly interface with just enought style to make it stand out without getting in the way. It also has a very active and helpful community to assist with any issues that may arise, and plenty of detailed tutorials are out there. There's a newsgroup devoted to Dolphin (comp.lang.smalltalk.dolphin, easy to browse through Google groups...) that remains busy and has lots of good info. The people at Object Arts seem to be
very helpful there, consistently chiming in and helping people out with questions/problems/etc..
I've also heard good things about the book 'Dolphin Smalltalk Companion' by Ted Bracht. While it may be a bit dated by now, I found that Amazon had some inexpensive used copies available, so I've ordered one and look forward to working through it.
I found Dolphin's various browsers and other tools well thought out and easy to use. As I did some simple projects in it (doing their tutorials, or some exercises in the book "Smalltalk, Objects, and Design", for example..) I realized I was meeting my
primary goal in all this: having fun!! Dolphin's environment 'clicked' for me, and I'm enjoying working with it, and will be using it going forward as I get to know Smalltalk better and begin trying my hand at graphics/game development within Smalltalk. IMHO, they've really nailed the balance between a Windows-specific focus, and Smalltalk tradition.
If you want to take a look at it, then check out
Bitwise Magazine's free download for the 'Value Edition'. Their discussion of Smalltalk itself is a fun read too.
I'm also keeping my fingers crossed that the ever-looming next release (v6) seems to be actually/really/this-time-for-sure almost ready to go. There's lots of great looking new features in it. Check out
Dolphin Map for a nice overview of the features, and Object Art's own
What's New page for an in-depth look at one of those features: a significant addition to their UI that they're calling the 'Idea Space'.
So, I'm very happy to have found the tool of choice for myself: Dolphin XP!