The best dreamcast boot disc software is bin2boot, binhack and mkisofs. The best packages the utilize these programs are Exoboot or a simple batched version called MakeCDI released here by a member almost a year ago. There's also Selfboot that can make selfboot images with CDDA tracks.
My favourite boot disc is still probably Utopia Boot Disc series. I have versions 1.1, 1.3 and 1.5. Also version 1.0 somewhere on a recordable.
I didn't know there where Boot Discs other then the Utopia Series. So I can highly recommend an Utopia Boot Disc. But I personally prefer making a game selfbootable .
Most games are selfbootable. Only a small percentage is not so taking the time to make these selfbootable isn't such a hassle and not so complicated anymore.