Every TC install resets your Main menu (not toolbar).  The *.mnu files are usually kept in the Language subfolder of the TC main folder.  It is an annoyance, but after every install, re-identify your saved custom menu file from Start->Change Main menu...

Also, keep in mind that the TC default main menu shows only a few of the possible commands (crazy, huh?).  Most TC users customize the main menu.

Fully populated menus are available here and a pack of tools (you may already have these) for customizing TC is available from here.

A little tip for customizing your own menu: you can split the menu between left and right sides of the TC window by placing the HELP_BREAK command in the mnu file where you would like the division to occur.

FireFox is OK, I guess, and I like its add-in model.  But if the Mozilla team doesn't implement a full featured page-zoom a la Opera with "fit to width" (not the low rent zoom behavior of IE 7), then all the fancy Addin/GUI/keyboard functionality in the world won't matter to me.

I agree with all your points except:

fails to provide me with an alternative to the dual-pane display mode.

You can set the SC panel divider to 100% (or 0%), turn off the tree, maximize the SC window, turn on the thumbs, and have the full screen to organize your thumbs.  Save that as a named layout, put the built-in layout dropdown control on a tool bar and switch to it instantly.  Voila! 

Or even simpler: just put SC's built-in 100% button on a toolbar.  You can see that button (along with other panel control buttons) on the bottom toolbar shown in that SC graphic in my previous post.

I should add that SpeedCommander doesn't seem all that speedy compared to Salamander or xplorer2.  A sticking point for me.

Salamander has by far the slickest/smoothest "seeming" interface behavior and appearance.  It's like silk.  Scrolling long panels of thumbs in Salamander is especially smooth.  The Salamander helper dialogs for copying/moving etc, are also excellent, though they have fewer options than TC's do (the leader in copy exception dialogs, IMHO).  Sometimes the sheer attractiveness of the interface makes using a program more pleasant than another.  Salamander is a joy to use, in that regard.

One nice thing about the Dopus thumbs display is that you can put a slider in a tool bar and resize the thumbs on the fly without having to enter the Options dialog. 

Finally: No problem here with a nag screen if I haven't paid.  I only open programs once between system boots, anyway.