I have a 24" in my collection. I like it and could work with it everyday if I had to and wouldn't be upset. However, as a primary I would be at 27" minimum by my own choice. In an ideal world we could choose from 21, 24, 27 & 32. As an aside, I would buy a 17" macbook tomorrow if they relaunched in that size.
Three times in the past, I was worried about screen size being too big.
When I got my 17" MBP, my 70" flatscreen TV, and my 27" iMac. I didn't regret any of those decisions. The wow factor doesn't actually last that long and I got used to all of them very quickly.