I wouldn't dismiss the Catalina 30's - they are great boats for a family. Beamy and comfortable with a decent cabin layout for 4 or a few more.
I'm in the pricess of (hopefully) buying an Allmand 31. The "tri-cabin" lay-out is nice for a family, too. The Hunter 28.5's also have a similar layout, though the aft cabin on the 28.5 is a little more cramped (not surprising, given the difference in length). The Allmand only came in a shoal draft (3'10") keel, and the Hunter was made with shoal (3.9') keels as well.
The Islander 28 gets great reviews and is a stunning boat. It has a more traditional layout with a quarterberth, but the interior is stunning, and the cockpit, if it's equipped with a wheel, is a good size for 4. There's a shoal draft version that runs 4'.
Another option would be the O'Day 272's - the wing keel on those should be good for you. If you have the budget for it, the O'Day 302 is also a nice boat with a good, shallow draft as long as you don't mind a wing keel. I'm told they aren't the greatest boats when it comes to their sailing ability, but as you'll hear over and over on this site, every boat is a compromise. I found the O'Day 272's cockpit to be a bit on the small side, especially if you're planning on having more than just your family aboard. 6 could probably squeeze in 272LE's cockpit, but the tiller version would be VERY tight unless your kids are on other people's laps.
I had a 1984 Catalina 25 with a swing keel. I'll tell you that the cockpit on that boat, and I think it's true on the O'Day 25 too, is tight for any more than 4 (or 3, really). We have 2 boys, now aged 7 and 4.5. Last season, the boys were always wanting to help steer the boat (which I think is a good thing, keeps them interested and occupied), and they were constantly getting hit with the tiller. Ok, maybe constantly isn't a good way to describe it, but the tiller posed real limitations because we'd have to wait for the family to shuffle around before I could come about. That has made me look to wheel-steered boats this time around. Many folks here and on other forums strongly advocate the preference for a tiller over a wheel on anything under about 35' because you get better "feel" for the boat, there are fewer moving parts to break, etc., and in many ways I think they are absolutely right. However, for my family and me, a wheel essentially became mandatory, especially if we wanted to have more people aboard than just us. I would encourage you to bring your family along as you "test drive" different sailboats, and see how the cockpit feels when you're all in it. Pretend you're out sailing - can you easily get to the lines
you'll need (including going forward if the lines
aren't lead aft) when your wife and kids are in the cockpit with you? If not, it will make for a less than enjoyable time out, and that's not really how I wanted to spend my time or my money. The Allmand has a very large cockpit, nice coamings, and access to the foredeck is great compared to my C25. From what I've read, she won't sail to windward very well, and she won't be all that fast, but for my purposes she's a good choice. The same is largely true of the C30 with the shoal draft, though those will probably have better pointing ability.
Switching back to the Catalina 25, the cabin was fine for us, though if you're planning on sleeping over, you'll have to get used to the idea of making up, and breaking down, the bed that either you or your kids sleep in. The "double" berth that I believe is under the O'Day 25's cockpit is really better suited for storage than sleeping. If you're only going to day sail, that's entirely different, and the cabin should be OK for the 4 of you. Again, my experience is based on a Catalina 25, not an O'Day 25, but for most practial purposes the boats are very similar.
I think you'd be better suited to look at something in the 27-30' range (or larger if you're comfortable with handling the bigger boat, and the costs that go along with it) rather than the 25, though the easy trailerability of the 25's is a big plus.