Any of those boats would work out well. If you're interested in racing, you might select one that has an active fleet. You are correct that this is a good way to get into sailing (one of the least expensive). You can learn a lot on a boat of that size.
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