My kids' book I sent out eight query letters, beginning back in December of last year. I got four rejections and then a sale in April. Never heard back from the other three publishers, and one of my rejections was actually a really great one from Elizabeth VanHouten at Bloomsbury, who said that she had really liked it (laugh-out-loud funny, she called it) but just didn't think it was quite what they wanted.
My young adult novel I sent out to nine publishers, beginning in May 2004. I got several rejections, and then in April of this year I got an acceptance. However, for a variety of reasons I withdrew my sub from the company that was interested, and re-pitched it to a couple of other places. I heard last week that the publisher who is doing my kids' book wants my YA novel too -- along with its two sequels.
My romantic suspense (adult) was something I shopped around for a year to about fifty publishers and agents. Then I did some serious revamping, changed a lot, and basically rewrote the entire ms from the ground up. I began querying agents in July, and a couple of them have it in review. I'm not bothering to approach publishers directly with this one, so hopefully an agent will offer to rep me eventually.