Two days isn't enough for a true Disney fan; three days with park hopper tickets would be better. This is Walt's personal park, not a corporate clone. Be ready to be charmed.
The following are rides at Disneyland and DCA that do not exist at WDW. You would do well to focus on this list first:
Disneyland
Finding Nemo Submarine Voyage - E Ticket
Matterhorn Bobsleds - E Ticket
Indiana Jones Adventure - E Ticket
Storybook Land Canal Boats - D Ticket
Casey Jr. Circus Train - C Ticket
Roger Rabbit's Car Toon Spin - C Ticket
Pinnochio's Daring Journey - C Ticket
Alice In Wonderland - C Ticket
Mr. Toad's Wild Ride - C Ticket
Snow White's Scary Adventure - C Ticket
Sailing Ship Columbia - C Ticket
Davy Crockett Canoes - C Ticket
Sleeping Beauty Castle Walk-thru - A Ticket
Disney California Adventure
Radiator Springs Racers - E Ticket
California Screamin' - E Ticket
Mickey's Fun Wheel - D Ticket
Goofy's Sky School - D Ticket
Redwood Creek Challenge Trail - D Ticket
Monsters Inc. Mike & Sulley To the Rescue! - C Ticket
Luigi's Flying Tires - C Ticket
Mater's Junkyard Jamboree - C Ticket
Golden Zephyr - C Ticket
Silly Symphony Swings - C Ticket
Jumpin' Jellyfish - B Ticket
Flik's Flyers - B Ticket
Francis Ladybug Boogie - B Ticket
Tuck n' Roll Drive 'Em Buggies - B Ticket
Heimlich's Chew Chew Train - B Ticket
Red Car Trolley - B Ticket
Then you have to consider all the rides at Disneyland Resort that are noticeably different than the clones at WDW. Many of these Anaheim versions are noticeably superior, have longer ride times, or have a high quality of showmanship and maintenance compared to their WDW cousins. But they are at least noticeably different than the WDW version:
Pirates of the Caribbean (A Must! See the missing seven minutes of ride time hacked off the WDW copy)
Haunted Mansion
Big Thunder Mountain (very different!)
Space Mountain (very different!)
It's A Small World
Splash Mountain (one of the few rides noticeably inferior at Disneyland)
Buzz Lightyear's Astro Blasters (removeable guns)
Jungle Cruise
Peter Pan's Flight
Tarzan's Treehouse (the Robinson family moved out)
Pirate's Lair on Tom Sawyer Island (very different theme)
Grizzly River Run (Kali River Rapids with 3 extra minutes and one extra drop)
Disneyland Monorail (kind of a ride, not really transportation)
Tower of Terror (a different show, no Fifth Dimension room)
The Many Adventures of Winnie The Pooh (not as good at Disneyland)
Disneyland Railroad (Grand Canyon Diorama and Primeval World viewing)
Disney Animation (a collection of exhibits, Turtle Talk, Animation Academy, and WOW! visuals inside)
So that's 45 various rides/attractions that either don't exist at WDW, or are noticeably different at Disneyland. You'd want to focus on those 45 attractions first, choosing the ones that most interest you. You can't do all of them in 3 days likely, but it's a solid selection to choose from.
Then there's the rides that are identical to their WDW versions, but have differences mainly in the facades or queues or pre-show areas. You could skip these in Anaheim unless they are personal favorites:
Star Tours
Midway Mania
It's Tough To Be A Bug (but with upgraded HD projection)
MuppetVision
Captain EO
Enchanted Tiki Room
Fantasyland spinners (Teacups, Dumbo, Carousel)
Little Mermaid (no Fastpass, always a 5 minute wait)
Main Street Vehicles
Mark Twain Riverboat
Gadget's Go Coaster (rethemed Goofy's Barnstormer)
Autopia (same concept as Speedway, different scenery)
Soarin' Over California (rumored to be getting HD upgrade for 60th, so could be worth it then)
There will be new parades for the 60th Anniversary next year; a rumored night parade and a new day parade for Disneyland. There's the Pixar Play Parade daily at DCA. You won't want to miss World of Color water spectacular one night at DCA, and Fantasmic! has much higher showmanship standards and different scenes at Disneyland. There are excellent major stage shows in both parks; Mickey and the Magical Map at Disneyland and Aladdin at DCA. But you at least need to see the two major water shows and the fireworks, and you'll need at least two full nights to do that.
Study up and figure out what's important for you to see and what you can skip. Realize there are as many rides and major entertainment offerings (parades, water shows, etc.) in the two Disneyland Resort parks as there are in all four WDW parks combined. You will be very busy.