Cruising with your family can be a wonderful experience for you all. Our family of four upgraded to a Catalina 30 from a Catalina 22, and that really opened the possibilities for us.
We had a hard time spending weekends on the C22, but we're good for over a week on the C30.
One way I justified the added expense was that we consider sailing our vacation, instead of taking a big trip somewhere. We spent a total of almost three weeks on the boat last year, which more than justifies the expense, I keep telling myself.
This month's Practical Sailor has an article on the sort of boat you are looking for, featuring the Catalina 30, Pearson 30, and Tartan 30. You can get a lot of boat for the money.
One thing also to keep in mind is that an older boat won't depreciate much more...
Your family will grow up fast! Get the boat if you can!
1987 CS 36 Merlin "Kyrie"
"They drove a dump truck full of money up to my house. I'm not made of stone!" -Krusty the Clown