We went over the 4th of July and it was the best time I have ever been there. The crowds are part of what makes it such a great place imo. We saw JLO there which was really cool for my wife and meh for me for some reason. As mentioned fastpass works very well and if you do the 5 for 3 you will do everything that you could ever want to do at Disney/California Adventure. If you want to save some money go to the dis boards and get some tips from there. The 5 days for 3 deal is likely still on? Get your tickets at either
http://disneyland.disney.go.com/disn...ketListingPage or
http://arestravel.com
Seaworld also had a 2 days for 1 deal when we were there. I would skip Legoland though as it was a big let down for us after 5 days at Disney and 2 at Seaworld we were basically going through the motions there and would have rather spent another day at the beach. Stick to the Dis boards and mousesavers and buy your tickets before you go and you will get good value! Don't forget to eat lot's of Churros!!