check each territory by it's bonus/territory ratio, and find the area with the best combination, and least likely chance of being contested..
w-e Africa are widely considered some of the better spots because with a bit of luck you can get 4 bonuses with only 4 borders..
If you start in a large bonus, -Canada, Antarctica, E.Russia, Australia, South America, Greenland- There is no point in continuing most of the time, especially if your aiming for the gold star.
Anywhere in Asia is bad because of the large borders you will likely end up with when you find opponents, and the only real good ratio's are india, caucasus, E.china.
Scandinavia and Mexico seem like good spots because the initial bonus can be done on turn 1 with a bit of luck, but Scandinavia has little in expansion possibliities, and Mexico requires you to capture N.America before anyone gets in, or risk a futile war keeping your bonuses in tact.
bonus armies/territories
Canada 7/10 70%
W.US 5/7 71%
E.US 5/7 71%
Mexico 3/4 75%
S.Am 4/8 50%
Ant 4/7 57%
Green 4/7 57%
Scand 3/4 75%
Europe 6/9 66%
W.Rus 5/8 62.5%
C.Rus 5/7 71%
E.Rus 6/10 60%
Caucasus 6/6 100%
W.Chi 6/7 86%
E.Chi 4/5 80%
M.East 4/6 66.6%
India 4/4 100%
Indo 3/5 60%
Aust 4/8 50%
S.Af 3/5 60%
W.Af 4/5 80%
E.Af 4/5 80%
N.Af 3/5 60%