Steve? 100gb music. Is that it? seriously need to get that broadened. And if you want something fast drive wise go solid state if you got dough. Don't know if the new USB 3 was incorporated with MacBook?
Only good SSD's are worth it (read expensive), we've done some testing and my bosses SSD is about the same read/write as my normal hard drive, only marginally better and not worth the £100's extra for a crap SSD

They also have a higher failure rate than normal drives