Here are the alien bees:
http://www.alienbees.com/b800.htmlthey are only $279 each. They are about the cheepest light that is decent on the market from what I have heard. But, if you are willing to spend $50 more, you can get White lightning UZ 800's. They are being discontinued right now, but as long as they still have the parts to make them, they will:
http://www.white-lightning.com/uz800.htmlI have 5 of these, and they work great. They are heavier duty than the alein bees. The casing is sturdier. I have two friends who have the bees, so I have seen them. They work nice, but the casing is plastic, and not as sturdy. They are made by the same company. I think both have a 5 year warenty on them. I had a problem with one of mine last month for the first time in the 3 years that I have owned them. I sent it to the company, and I had it back in a week and a half, no cost. They also have great customer service. I have called a couple times with questions, and they have always helped me.
If you go with the Bees or the White Lightnings, I think the 800 watt would be good. You shouldn't need more than that for an indoor studio at home. The 400's might not give you enought power for something you want to do.
I started with 2 800's, then one more, then 2 more. I also bring a set of them for formals at weddings.