Workflow to Clear Out the Clutter

This question has probably been asked before, but I'm looking for the best workflow to completely go through my collection of digital photos and clear out the junk so we can enjoy the best photos we have. I have around 50 gigs of photos from the past 10 yrs or so, so I have a lot to go through. I'm not a professional, these are pictures of family, friends, etc. No photos are currently in RAW format, although I'm considering switching to RAW once I figure out what to do with all my existing files.

GOALS:

  • Eliminate photos that are either junk or near duplicates where I took a bunch of shots looking for the perfect shot.
  • Add basic metadata/keywords to photos in order to facilitate searching.
  • Perform basic adjustments to the photos I keep and save/export the changes (I'm not sure exactly what to do here)
  • Create a collection of great photos that can be easily accessed using my HTPC.
  • Upload photos to a photo sharing site, likely Flickr, for easy mobile viewing and for a backup of my best pictures.

TOOLS At MY DISPOSAL:

  • Lightroom 5 (came free with the recent purchase of a new laptop-nice extra)
  • Picasa
  • I have existing accounts at Flickr, G+, etc.
  • I use Crashplan for backing up all my PCs, so I'm not concerned about cloud backup for protection from hardware failure/disasters.

Please note that other than a few trial uploads, I don't even have my photos imported into Lightroom. For the most part they're just stored in folders by date currently.
Thanks in advance for any pointers.