If you have used an OM it must have been quite a step to a point and shoot.

It all depends on what you want to do and what quality you want. In the old days, a film had a certain sensitivity, expressed in ISO (asa, din,...). Digicams have a range of sensitivities. Which is very good for less light situations, but if you want some quaity, a DSLR is better because less noisy.
So if you can invest the money, you're always better off with a dslr like the 400.
I'm not shure, but the lens that came with my 350 was really not good. The 400 comes with the same lens so I would go for a body only and add another lens. I personally have Sigma lenses, but other brands can be good as well.

But it all depends on what you want to do with it. A dslr is the best, but you'll effectively be spending $1000. As I live in Europe, unfortunately I can't advise you where to buy.

There are no Borg. All resistance is fertile.