if you kids have trouble with a lot of walking, make sure to take or rent a stroller. one year, i thought 'oh they're big enough now to stay up and watch the fireworks' and the next day was hell with the whining. anyway, you'll get more mileage out of them if they don't have to walk everywhere, plus it's good for hauling stuff.
my kids (2 girls 7 and 5 at the time) LOVED, LOVED, LOVED buzz lightyear. miraculously, you even get the ride pictures for FREE, sent to your email if you want to stand in line at the kiosk at the end.
if you want to go on finding nemo, go first thing. once time when we were there, it was an hour wait to go on the darned thing. it's not that exciting but your kids might insist.
my kids did not care for toontown very much and the roger rabbit one is a little scary.
we also rode a lot of dumbo. we had grandparents with us so we staggered the adults in the line so that when the kids were done with one ride, they could get right back on with another adult.
catch some of the free shows. they make for good breaks. there used to be a princess one by toon town that was good.
the mountain rides are fun but could be scary, depending on your kids. my oldest loved space mountain but my little one was too small anyway. materhorn really jerks you around. there may be a scary part in splash mountain, plus you have the sudden drop off.
there are a few rides that i find boring but the kids like: small world, alice and wonderland, the caterpillar ride in california adventure (it's the worst!), casey jr. train ride, and the boat ride in storyland. tom sawyer's island is fun to run around on but be prepared to go through tight spaces and remember there is no bathroom!
indiana jones throws you around a lot (can you tell i have neck problems :P) and was too rough for me. you have to do pirates but it might be too scary for your kids. the drops are in pitch-black to start and then it's dark down there and loud from canon shots.
in the canoe ride, there are no motors other than you so be prepared to work (and maybe get splashed)!
if you're going in california adventure, i highly recommend the muppet show. the ant show is good as well but can be a little scary. hmm, there is some loud parts to the muppet one as well. you've GOT to go on the toy story ride, if only once. when we were there, there was no fast pass so the wait was LONG. soaring is fun but not for the motion-sick. the roller coaster (sorry forgot the name) is also jerky. there's a fun little play area for the kids to run around in and a little rock wall for them to 'climb'.
watch out for the prices :P we usually bring in as much snacks and water from outside that we can. if you're driving, get yourself to costco or some such to stock up.
you picked a good time of year to go, the waits will be much better. if you are going in the middle of the week, you'll be doing even better!
have fun!