What are you using for a flash? A fairly powerful external flash will allow you to use a smaller aperture for a better depth of field (if that's one of your concerns). Better yet, I like to use a remote flash to give me a little shadow and some texture. With my D40 I also set the color balance to "flash" (rather than "auto" which seems to give me the best color results (and also avoids the extra flash that tends to make the animal move just as you shoot).
-----
What goes up must come down...unless it exceeds escape velocity.