domain.com Vs. domain.local ?

Hello Everyone,
This is my first post and sort oif a newbie question. I recently setup win2k3 with A/D, DNS and DHCP. My question is, when i setup active directory i used the following domain for a single domain controller in a new forest:

domain.com instead of domain.local, like i have previously seen else where.

-Did i make a major booboo by not using .local instead of .com?
-will my DNS performance or any other aspect of my A/D suffer as a result?

Thanx for taking the time to read this. Any info is greatly appreciated.
p.s. i will clarify gladly any detail that seems vague.