We went there (and CA Adventure) for 3 days a year ago. My boys were 5 1/2 and 1 1/2. I had a great time, as did my kids - DH not as much, but I think he still had fun.
No time to read the other posts, so sorry if I've duplicated.
Most height requirements on the major rollercoasters were 45", some 52", but my 5 yr old (at the time he was 49") didn't want to to ride those anyhow. A ton of the rides don't have requirements at all, so we all could go (e.g. Pirates of the C., Haunted House, etc.). Our littlest got a little scared on some of the dark rides, but mostly he was fine. I was actually amazed at how many rides we could all go on as a family. Disneyland definitely caters well to families. And the place was so clean! They were sweeping up DS' crackers seconds after they'd hit the ground.
My tips:
take advantage of the fast pass program for the rides that have them. If you/DH both want to ride, you can 'share' the same fastpass - i.e. go to the head of the fastpass line with your partner, and they will hand you a pass to use when he is done riding. The fast pass line might be 5 or 10 mins long while the regular line would be 30 to 45 mins. DH and I would trade off riding with my 5 yr old, so DS would get to go twice, and mom and dad each once, while the other watched the toddler.
Is your 2 yr old pretty good at sticking near you? If not, I would highly recommend a leash. I sooooooo wished I'd had one with our toddler. He wanted to run around, but I was afraid he'd get trampled or lost, so mostly he was confined to the stroller or soft carrier (also a lifesaver). I saw a man go by with a toddler in a leash, and was so jealous. What a great idea! The toddler and dad were both happy!
Definitely bring a large roomy stroller - double if you have one. Even my 5 yr old sat in it for a while when he got tired by the 3rd day, and I would keep DS2 on my back (in the soft carrier). The rental strollers are around $10/day, and you can't take them back to your hotel. When the kids aren't in the stroller, you will still have a place for all your crud. There is plenty of stroller parking for when you go on rides.
Have fun. I want to go again, but I think we'll wait until DS2 is at least 4, maybe even 5 so that he can go on more rides.