The biggest differences you will notice:
Pirates at WDW does not have all of the 'intro' stuff, such as the caverns, skeleton scenes (except for the skeleton steering the ship in the lightning) or the number of drops as at DL. There is also no 'outdoor' portion (where the Blue Bayou is at DL). But the WDW queue is really cool, going down into the 'dungeons'.
HM at WDW has a different exterior, and a fun interactive queue. There is also an 'interactive' portion at the end where the 'ghosts follow you home' that you do not get at DL (they can't implement it because they don't have the physical room for the projectors). You will notice other minor differences, but these are the big ones.
IASW at
Disneyland has a beautiful exterior, with the clock 'show' every 15 minutes. They have also integrated Disney characters into the ride in a lovely way (mostly non-intrusive, with the exception of Ariel). Taking the characters and exterior out, the rides are otherwise similar.
One thing you will notice at WDW is that Jungle Cruise is much longer and more elaborate. It used to be this way at DL, but half of the ride was taken out to build Indiana Jones. WDW also still has the Swiss Family Robinson Treehouse and original Tom Sawyer's Island (with the forts and guns that 'shoot') Peoplemover, Carousel of Progress and Country Bear Jamboree. DL has Snow White and Mr. Toad, which no longer exists at WDW. Buzz Lightyear is much better at DL, because you can take the guns out of the holster and actually see your 'beam' as you shoot. Space Mountain is a personal thing, but many people like it better at DL, because of the side-by-side seating and musical soundtrack. Autopia/Tomorrowland Speedway is much more themed and fun at DL, as is the railroad (the Primeval World segment isn't at WDW). BTMRR has a better queue and ride at WDW, but they're missing the fabulous 'dynamite explosion' sequence you get at the end of the DL ride.
Those are off the top of my head, I know there are other comparisons!