If you're staying in Anaheim while going to the Ducks game and Disneyland, you can check out the Downtown Disney district, which is right beside Disneyland.
There is an ESPN Zone, so if you're looking to watch the mass suicides in Vancouver and/or Edmonton, that's a good place to catch a game. I was even able to watch the Grey Cup there last year, and met a couple of other Flames Season Ticket holders watching the Flames-Sens game. No cover charge, but the food isn't cheap. The burgers are great though. There's also a sports-themed arcade upstairs.
Also at Downtown Disney, there is a House of Blues. They have concerts there - you do have to pay if there's a concert, otherwise I believe it's free. Website:
http://hob.com/venues/clubvenues/anaheim/
I don't know much about the rest of the night life in Anaheim (if there is any), but as already mentioned there are a few places around the Pond and Angels Stadium. I seem to recall a good taco restaurant just west of the Stadium on Katella, I seem to recall something like 99¢ beer (which could explain the fuzzy memory) and 50¢ tacos and they're much better than Taco Bell or Del Taco.
I wasn't really impressed with the Pond (and its tiny crowd - I bought "scalped" tickets for half of face value), but Staples Center is a great arena - not quite the atmosphere of a Flames game, but what is? You could actually walk around the concourse during intermission, and the doorway to the washrooms was wide enough for people to walk in and out at the same time. The Pond was easy to get around as well, but there were more people sitting on the players' benches than in the section I was sitting in, so I'm sure that made a difference.
I wasn't really all that impressed by Universal Studios. It has a few rides, but the Jurassic Park one is the only one worth going on more than once (but only if it's warm because you do get wet). The Studio Tour aspect of the park is nice, but it is very sanitized for the public. The closest you'll get to seeing a celebrity is driving past Jill Hennessy's parking spot outside the sound stage where they shoot Crossing Jordan. You might get to go down the street where they shoot Desperate Housewives, but only if you go on a Sunday because they shoot the rest of the week (although, they might be done their season by now). Everything else on the tour (Jaws, King Kong, Earthquake, Mummy, War of the Worlds) is set-up for the tram tour. My favourite part is when you go past the sets of Whoville from The Grinch, then around the corner to the Bates Motel from Psycho.
If you want to see a real working movie studio and actually get to walk around the backlot, go to the Warner Bros. tour instead. It was great. Instead of a huge tram with about 200 people, you ride in a cart with about 10 people and you actually get to step off and walk around the lot. Every tour is different because they have to avoid the areas where there is active shooting, but I was able to see the Ambulance bay from ER and the whole town where the Gilmore Girls live. You really get to see how poorly everything is constructed.
We also walked around the hospital set from Invasion and the office from Without a Trace (amazing - I don't watch the show, but their soundstage is incredible). They also had the set from Central Perk from Friends set up in a storage room, so we all got our pictures taken on "the couch" (the guide said we weren't allowed to, but let us anyway, I'm sure they say that to everyone).
The WB tour is 2 hours long and is about $10 cheaper than a full day ticket to Universal, but if you want to see a real movie studio, it's totally worth it. The entrance to the WB tour is about 2 block away from NBC (which doesn't have any public parking, so you have to park a few blocks away on the street), so you could do the WB tour in the morning, the NBC tour in the afternoon (not that great, but super cheap - about $6 if you're an AMA member), then stand in line for the Tonight Show.
I didn't see any celebrities, but the guide at WB said they occassionally have actors hitch rides on the tour carts. He specifically mentioned that George Lopez and Martin Sheen like to tag along the tours every once and a while. However, the tv season is almost over, so they might be done shooting before you go.
As for celebrities, if you can find out where there's going to be a movie premiere, you might see some if you can get close to the red carpet. Last June, I was in Hollywood the night of the Batman Begins premiere, and saw Morgan Freeman, Christian Bale, and Liam Neeson arriving. I also saw Tom Cruise and Katie Holmes arriving (she's like 6 inches taller than him). They all talked to Access Hollywood and ET on their way in.
Of course, going to the Tonight Show should guarantee a few celebrity sightings. They'll probably also show a few on the Jumbotron at the Kings game - they showed Jesse James (from West Coast Choppers) at the game I went to.
The closest I got to any celebrity sightings "in the wild" was at Disneyland. They're usually escorted by special tour guides, so if you see a tour guide (they wear red and blue plaid vests - and they're the only ones in the park who do) walking along with a small group of people, look at the group, and there's likely a VIP of some sort in the group. I saw both Corbin Bernsen (not a big-time celebrity) and Maria Shriver (first lady of California - Arnold was giving a speech there that day) this way.