Portable home studies must-haves

[misol]

I am going to get a start up studio (I have been shooting in natural light for about 9 months and feel like its a good time to try my hand at studio work which I think is waaaay more difficult). I am kind of at a loss of what I will need.

I want it to be portable
easy to set up
versatile (portraits of children, older people, families, groups but generally more casual work)
I prefer very simple, clean backgrounds
I want to be able to switch backgrounds easily
I have $1500 to spend

Does anyone have a check list that could help?
Advice on lighting? There is so much information out there I have no clue where to start.
Advice on what I should look for in a light? Good brands?

Thanks so much for any direction!

[brhitch]

I started off with a People Popper setup and a couple of Alien Bee 800 strobes with 45 inch umbrellas. I have since added to that with a black muslin, a botero 2 sided muslin that I use alot and a botero black and white flex out. I also have a small light stand and double fold umbrella that I use with my small speedlights for quick setups.