Just my 2 cents...
This is my business... so I have a little different take on it.
First, since it is my business I got the best program you can (IMHO) - iLife. This comes with the purchase of a Mac. Before I got my Mac I used Roxio. It's got it's good and bad issues. If you're just wanting something basic then the programs listed before will be fine. If you are wanting a little more control and creativity then something like Roxio might be good, but be warned - it does have it's bugs.
As far as the music - I've talked in length about this very issue with several people in the business. With music (unlike with scrap kits) it's very very very difficult and VERY VERY VERY expensive to get a license to use the music. Especially if you're just a little in-home business.
Having said that - I make all my clients provide their music. Sometimes I can suggest something and if they don't have it they go and buy the cd, either way - they have to provide it. Otherwise they get the royalty free synthesizer music that's disgusting.
So, just wanted to offer up what I do.
Hope it helps ya a little!