Consistency is non-existent amongst apps. Even on OSX, for all their insistence on their Human Interfaces Guideline, the experience of using multiple apps is still a patchwork of styles. If your needs are fairly generic, you can assemble a fairly consistent set of apps, if you accept some that are crippled or plain lousy.

Not personal but I can't resist: "A foolish consistency is the hobgoblin of little minds." (Emerson)

That's an absurd notion. Is chrome inconsistent because it doesn't look like a GUI toolkit?

Yes, and it annoys the hell out of me. Even Chromium's "GTK+" theme doesn't look right next to other GTK applications, where as Firefox does.

Looking at something like gsmartcontrol I can only spot the few icons being different than the shell32 ones, so it's still more consistent than most commercial software.