|Alienbees are great, and so is Bowens, I'd suggest a 3 piece kit, it will set you back about $2000, but everything is included, softboxes, umbrellas and everything you need, and even a battery so you can use your kit outdors where there is no electricity.
I know it's expencive, but you could always buy the 2 piece kit and add the 3rd light later, that will save you about $700
but the 3rd light is actually really important in a portrait shooting..
here's an example
first the portrait
and then the setup