Sequential creation of site using WPMU and : do I need BP?

Well, I'll take the plunge. Here is a description of what I'm after. I love WP and would love to be able to create this site using WPMU as I will have a whole lot of members/bloggers. Now, I don't know if I'll need BuddyPress, but let me share a list of my needs here, if I may.

I'll be grateful if you could suggest plugins for each function/feature you think would be best suited?

I've done a few WP sites, but this is my first time attempting to make a WPMU site.

Thanks in advance!

styzer
Canada
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The projected website will present a collection of artists from 3 fields: music, writing and visual arts.

There will be three types of memberships:

- visitor
- member
- artist

VISITORS - FREE- No account.

Browse freely.

MEMBERS - FREE- Account. Registration needed.

Has a member page.

Has a blog.

Has a simple music player.

Can create playlists from free offered music (stock photo websites lightbox concept - one-click to add to a playlist). The music could be played on their page via a media player. Some artists won't offer free music, others will.

Display a number of feeds from favorite artists, which will show on their member's page, showing those artists latest blog entries.

Follow artists blogs.

ARTISTS - FREE- Account. Registration needed.

Has an slightly customizable artist page.

Has a blog.

Media player (audio and/or video), a store area.

Maybe other functions as things evolve.

Minimal customization possible at some point.

R E G I S T E R E D

========================================
- MEMBERS : login/logout.
========================================

Control panel -

Visually separated sections:

1- member's details and informations
=> selectable personal info to be made public/private will constitute profile
=> purchases history
=> display playlists

2- member's mailbox
=> shows latest communications /pm
=> shows online friends (?)
=> display favorite artists latest blog entries

3- member's contributions and interactions
=> blog entries from the member
=> WYSIWYG text editor, with publishing button
=> latest comments to be approved

========================================
- ARTISTS : login/logout.
========================================

Control panel -

Visually separated sections:

1- artist's details and informations
=> selectable personal info to be made public/private will constitute profile
=> purchases history
=> display playlists

2- artists's mailbox
=> shows latest communications /pm
=> shows online fans (?) / friends
=> display selected favorite artists latest blog entries

3- artists's contributions and interactions
=> blog entries from the artist
=> WYSIWYG text editor, with publishing button
=> latest comments to be approved
=> event calendar

4- artist's store
=> display sales - albums, songs, books, other
=> display amount due to the artist, minus commission
=> create album/upload music, upload books
=> mp3 samples automatically created (?) at 128kbps
=> mp3 - minimum resolution for sale 192kbps, maximum 320 kbps (may require upgrading account due to files weight - tbd)
=> upload, edit, delete images for visual art (image resizing for display - high res only for purchase)
=> upload book excerpts (PFD) (look at copyright waiver/disclaimer for sign-up registration)

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