They do move all of the furniture, and it's a lot of rooms we have done. six bedrooms, two staircases, two living rooms den, office, various hallways. I want wood floors but we have a newborn and the wife wants to keep the carpet for now for "safety reasons." But I think I'll win the wood floor battle soon.

Bissel makes a really good home unit, about $150, had one for 10 years had to replace it when the kids used the bucket for it as a play toy and cracked it... gets used about 10 times per year, MUCH cheaper than renting unit or hiring stanley steemer, etc.

I've used the Bissel ProHeat for about 5 years and its great. Not as heavy duty as a commercial unit but great for keeping the off-white carpet upstairs clean. The nice thing about owning the unit is that you aren't pushed to do the whole job at once. I've used it to catch one spot or to do the whole floor. I know it works when I need it (unlike the time I dragged a rental unit home and it was busted) and it doesn't smell like it was used to clean out a horse barn. The rental machines were great when I was in college.
P.S. A buddy of mine that owns a carpet cleaning company told me the "tricks" to cleaning properly:
1) (As stated above) use less detergent than recommended
2) Take five times as long to suck up the water as it takes to put it down. Most people soak the carpet too much.