What do you mean you specialize in indoor photography? As a "specialist" you should know what equipment best suits your needs. There's a big difference in the functions between the two cameras but the end result (photographs) doesn't rely on having one or the other.
If you plan to shoot whithout a flash then a caera with a high ISO ability 6400 ISO with minimal noise is important....however if you use a flash then most any DSLR will work..and as blueiron said...lenses based on your work is critical...and much more costly unless you are getting into the D700, D3 etc...