Blog Technical Question

I'm thinking of upgrading to a better blogging platform.

I've noticed that to do some of the more complex posting, with sound, video and graphics I've cobbled together a Rube Goldberg patchwork.

It seems to me that an integrated blogging platform that easily organizes these elements on one server would be a better idea.

Also, I'm interested in better ways to manage comments and allow a fuller range of participation among regular readers. Some sort of registration enabling access to wider feature sets like an online message board while providing greater control over malacious commenters.

Any ideas?