I'm too impatient to read through all the replies so forgive me if this is redundant.
The co-op family school is beyond amazing, if you can get in there I highly recommend it. It should be easier for you to get in seeing as how you have an older child. Call them on Monday, if you haven't already. Of course, this presumes you will be at UO, but even if you're not you might still be able to get in as a community member since you'll be in the pre-k program.
I'd recommend them over Moss Street because you're never guaranteed to get the hours you want from term-to-term at Moss Street. This can be especially frustrating if you have a schedule change early in the term. It is a great facility but I have lots of friends who have had to scramble to cover hours because Moss Street didn't have room for them. (You request blocks of hours/days before the beginning of every term. They try to give you what you want, but often they can't. You might want FT on MWF and they'll offer you 10-2 on Thursday. ?)
Eugene public schools? Meh. My daughter went to Edison and Roosevelt and while those are some of the best schools around in the area, they are still not great by my standards. She is quite bright and capable but has a strong reading deficiency that the teachers never took seriously. Also 4J is practially on a 4-day school week. The budget situation is pretty bad.
I have friends who love the village school (public Waldorf) but complain/worry that their kids won't be prepared academically for middle/high school. I think that's a general Waldorf concern, instead of Village school concern. I've also heard good things about Ridgemont Montessori. There's not a lot going on for private schools. We toured Oak Hill, it's pretty groovy, but the classes are almost too small. (My daughter would have been one of 8 sixth graders.)
As for neighborhoods, it *really* depends on what you're looking for. I disagree that living near UO is too loud, but that's just me. We lived just south of 24th and LOVED LOVED it there. Lots of parks, lots of kids, safe neighborhood, close to the awesomest outdoor pool and community center (Amazon), and the greatest natural food store ever (Sundance). Whitaker is nice too and I often lamented not living there but ultimately we felt it was a) a bit too far from UO and b) really not as safe. If you want a community of tatooed and pierced mamas with very alternate lifestyles, that's probably where you want to be though. South Eugene is a bit more conservative and quiet, more university parents, less dudical ones. I love the hip-mamas of the Whitaker, so don't misinterpret that for a bash, but I DON'T love the alcoholics that roam the streets at all hours, the high prevalence of sex-offenders in the neighborhood. Sorry Whitaker moms, but all of Eugene's sex offenders are your neighbors. It's a bummer. Most of my friends with school age kids sold their houses and got out of Whitaker. Because, oh yeah, the neighborhood schools suck over there.
If you're going to move to South Eugene, I'd recommend staying between 24th and 30th. But that's just me. Past 30th gets really quiet and too boring, in my opinion. But it's also cheaper out there. I wouldn't go west of Chambers if you're moving west.