Anywhere I see an icon I'd also like to see the OS overlay. I have a custom mod of WndTabs (in VC6) with this and I find it very useful as I use TortoiseCVS/SVN and it therefore shows which files are modified since the last checkin, and other VCS metadata. Having the icons match the OS would also make it a little more consistent (not that I have particularly wacky icons).
Here's my code:
SHFILEINFO sfi;
SHGetFileInfo(path, 0, &sfi, sizeof(sfi), SHGFI_ICON | SHGFI_SMALLICON | SHGFI_ADDOVERLAYS);
m_TabImages.Replace(iCurrTabIndex, sfi.hIcon);
::DestroyIcon(sfi.hIcon);
It's probably slower than using a hard-coded imagelist so maybe worth making optional, or you could try to only look up the visible icons.