Multiple domain names and duplicate content, what's best option?

Hi All,
Am trying to determine how best to use optimized domain names in
conjunction with my main website. As I understand it, I have 3
options:
1. register optimized domain names and use 301 direct to point to
existing site.
a) Is there any benefit to having optimized domain names when doing
this?

2. register optimized domain names and use existing site template to
create "mini-sites" promoting services related to the domain name
keywords, migrate relevant content from existing main site and edit it
so don't get labeled as "duplicate content".
a) This option is a lot of work, will it give me the most SEO bang for
my buck??

3. register optimized domain names and use existing site template to
create blogs, migrate relevant content from existing site to each
blog.
a) My understanding is that I would not have to edit the content on
the blog as Google does not check blogs for "duplicate content". Is
this true?
b) Is this only true for blogs created in Blogspot or Wordpress?
c) Would it also apply to Drupal blogs???

I would really appreciate feedback on this. I have bits and pieces of
information but can't get a comprehensive picture of my options.

Thanks