The Brandy Manhattan in various formats has been my drink of choice for about 30 years. Never bothered with bitters but a shot of decent brandy on the rocks with just a tiny splash of sweet vermouth {nothing ruins a Brandy Manhattan quicker than too much vermouth, seriously just a little bit} works well for me.
If you want to kick it up a notch try adding {to the above formula} just a tiny splash of good bourbon. Best to build your own as I have rarely had any luck ordering them in a bar... they always seem to go heavy on the vermouth... arrrg!
:B