I suggest choosing the same discount broker to handle your IRAs and your taxable accounts. You usually don't have much choice with a 401(k), but choosing a low-cost provider of index mutual funds, like Vanguard, is one way to use efficiency to help your investments reach their potential.
Get started even if you don't read this article
The most important thing in any retirement plan is getting started immediately. I could have started ten years before I did and had a much better head start. You can't make up for lost time. So don't worry about your plan being perfect from the beginning. Doing anything is better than wasting time trying to know everything about investing before making your first contribution to a retirement plan. You'll have time to work out the details. Start today.