I'm far from the most organized person but thought I'd share my opinion. I would load all the files onto the portable drive and use a cataloging software to search the photos from the drive. I'd continue to maintain the files on CDs/DVDs so that when the hard disk fails you have a backup (preferably kept in a separate location). The archival life of the CD/DVDs is not permanent though and should not be thought of as such.
I myself have 65 Gb of photos and videos on my desktop, backed up on a separate external drive (connected to the desktop), backed up on a portable hard drive that is left at the office and some of it backed up on DVDs in a fire-rated box (mostly family photos that cannot be replaced or retaken). I sync the portable once or twice a month so I only run the risk of losing a few weeks of files in the event of a serious loss of data (both the desktop connected drives). I'm not burning DVDs as frequently. A more organized person would probably not have as much wasted redundancy but Mbs are cheap.