Upholding board's finding of no likelihood of confusion between marks after finding that parties' multimedia CD-Roms were not similar and had different channels of trade; one party's product was used strictly in the film and music industries and the other's was used in the fields of pharmacy and medicine.
Stating that "[a]s to strength of a mark . . . [third-party] registration evidence may not be given any weight . . . [because they are] not evidence of what happens in the market place"