Huntington is probably the closest to DL. Pier has a Ruby's restaurant and Main St. (which starts across the street) has plenty of places to eat.
There is a walking path on the beach & surfers to watch.
Santa Monica is one of my most favourite places. At the end of the pier there is a great Mexican restaurant with killer margaritas, we've also eaten at Rusty's surf ranch, and the allbright and I recommend them all. Wasn't too keen on the Italian place (name escapes me at the moment), and bubba gumps is standard everywhere. Also try the ice-cream at soda jerks, also on the pier.
It's a pretty easy walk along the beach to Venice if you were wanting to head there as well, or you can hire bikes.
I'm with usnuzuloose.
Take Harbor Blvd down and 55 Fwy back to Disneyland area and you'll get to see some of the best traffic Orange Co has to offer - and my #2 and #3 favorite beaches (#1 being Corona del Mar - for the cliffs, homes and beach).
If you want a close beach I would pick Newport or Huntington, both of them are great beaches and have a lot to do there.
I really love the Santa Monica pier, but that's not exactly close per se.
Another vote for Huntington. Newport is great, but it seems like you have to take the ferry over to the pier area and parking is hard? Am I remembering right?