There is no definitive answer to this age old question of which resort is preferable.
I love Disneyland for the sheer number of attractions, packed into a convenient space with plenty of affordable hotel options within walking distance.
I love Walt Disney World for the diversity of theme parks, more affordable options to stay in a Disney resort, and the superior variety of dining options.
For me, distance/travel is not the issue. WDW is a few extra hours flight time, and a few hundred extra dollars, but not a deal breaker. The difference is that a proper WDW vacation takes more time and money than a visit to the DLR, where five days is more than enough to do it all.
While I can't imagine restricting myself to one of the two, if money is no object I'd probably take a trip to WDW over DL. It's simply the more complete vacation experience.