I remember a post awhile back about how to drag a window from anywhere on the window. (not just the titlebar)
Someone just pointed this out to me, it's an undocumented "feature" which allows you to do this with a single call...
SendMessage(hWnd, WM_SYSCOMMAND, 0xF012, 0);
SC_MOVE + HTCAPTION = 0xF012
I found it extremely useful, maybe someone else will too.