First you will need to determine the size of your studio and the number of lights you plan to use. This will give you an idea of the power rating you will need to shop for. Determine your budget and if you will need your strobes to be portable, will they be used off location as well. I started out with photo-floods way back in the day. I have used multiple flash units with some success. ( 3 Sunpack 383's) I now use a couple Westcott Spider-lites and I like them a lot. Strobes will give you more light for greater DOF. I do a lot of animal and child portraits and the continuous light I use is less of a bother to critters and children, and the "what you see is what you get" quality of continuous lighting I find an advantage. At the low end of strobes, take a look at Alien Bee's. The sky is the limit at the high end.