I think that having the buddy list display on every page might be a little spammy, unless it was done in a simple format at the bottom on those pages, like the Users Online stuff at the bottom of the BoardIndex page

Personally, I think that there should at least be a single seperate page, that lists the buddy's Name in one column, the Online/Offline icon in another icon, a link to IM them in the next, and maybe a few other small informational things, like e-mail address, ICQ UIN, etc.. I don't think that your buddy list should be displayed on your profile,

Though I do think that on other people's profiles, there should be an 'Add to Buddy List?' at the bottom of it, if they're not on your list, and something else for if they're already on your list..
Or, maybe something similar to the Memberlist, but for people that you choose/ask to add onto your list, but displayed only to you. *shrug*