Own a canon sx200 is, but want to jump up to a DSLR, specifically the Nikon D90?

Hello, i have the canon point and shoot SX200 IS, which is a 12MP and 12X zoom camera. It's my 2nd point and shoot and I am pretty satisfied with it. It does have aperture and shutter priorites, and manual focus that I have never used. However, I want a DSLR, because they are very versatile when you look into the fact that different lenses can produce dramatically different results, I am ready to jump. At least this is my umption. I have researched and have decided on the Nikon D90; I want something I can grow into. I just want to make sure that I have umed correctly that I will be able to take better landscapes and capture my kids in their sporting activities better than I can with my point and shoot, of course with the correct lenses, which I will research later and probably rent before I purchase. Thanks for any and all relevant opinions/advice.