the1brit

I would like to create a simple niche blog directory (like blogflux and others) and would like some suggestions on the simplest and best approach to achieve this goal. I have worked with both Joomla and Drupal and I am fairly comfortable with each. I have also worked with Wordpress, but I am not really considering it for this project. The functionality I would like is:

1. Blog Submission - fairly comfortable in accomplishing this.
2. Automatic creation of screenshot / thumbnail of Blog website - no idea how to have this automated.
3. Pre-determined categories
4. Taxonomy / categories display to find blogs
5. Blogger profiles
6. Friends and other community type functionality.

Any suggestions on the best CMS to accomplish this and associated modules or components that will be needed? Also, links to web resources or other forum posts would be very helpful.

Thank you in advance!