I get that a lot of photographers consider Ken Rockwell to be irrelevant at best and a source of wild and unsubstantiated craziness at his worst, but I've come to find the core of many of his arguments to be quite valid. If you read the article I linked above you'll find some great reasoning for becoming conversant with one lens and one camera body. Hopefully the least complicated body you can find.
I've written similar essays and I've come to the same conclusion: More gear = less good photos.
The image above is of Sarah L. I wanted to use her on the cover of my third book but my publisher and I didn't see eye to eye on that one. When I shoot portraits I generally shoot them with the same lens and the same settings. Even the light is largely the same. That's because the portrait is about the subject and not about the technique. If the technique is the first thing you notice in one of my portraits that means I've failed. Miserably. The camera is out of focus and Sarah is in focus. And that's the way I meant it to be.
Give Ken his due. He gets it right more often than a lot of would like to admit.