Position!

MTW-Denmark
RTW-Brittania
MTW 2-Scotland (Once I conquer that northern province)

Oh, and when I wasn't taking my Prosac, color. Yep, color was a deciding factor for me for a while. Never played HRE. Black and yellow, just not menacing or cool. Also never played the Byzantines. Purple! The only reason I have ever played Poland in MTW, is because of the color, and cool flag.