We all need one good TTL hot shoe speedlight for walk-about bounce use (do use your white bounce card). And that result can be mighty good too, but then we often wonder what happens if we try a little harder? Off camera lights make a big difference. Umbrellas make a really big difference - when up close they give very a soft light, very flattering for portraits. And another light or two makes a really big difference too. The question then is which way to go? It is easy to put speedlights into umbrellas, and this works well. Or we could get actual studio lights. The following comparison speaks of more studied fixed setup multiple lights, like for umbrellas in the living room. The following about the difference is intended to be an introduction for those not yet familiar with these studio practices. There is a strong Nikon bias here, but much of this is not brand specific.
Speedlights vs Studio Lights.