I have great hair naturally. I'm also extremely modest.
Really, though: my hair doesn't need much help to be shampoo-commercial worthy. The trickiest part is dealing with the thickness - if it's moisturizing enough for the dryer outer layers, it tends to exacerbate my already oily scalp. If it gets my scalp clean, it tends to dry out my hair. You get the idea.
Suave Professionals Rosemary + Mint Conditioner has been my hair's favorite thing for a good two years or so now. It's just the right texture (not too thick, not too watery) to easily work through my hair without having to use half the bottle in one sitting. Even if I rinse out every trace, it leaves my hair smooth and nearly effortless to detangle. It never leaves buildup or causes greasiness, never breaks out my scalp or back, even when I use it for several days in a row. It smells like wonderful herbal mint, and gives my scalp a light tingly feeling. It's dirt cheap, about US$3 for the biggest bottle (36 oz, I believe). Even the packaging is my favorite kind, an upside-down squeeze tube.
I have this vague frisson that it's going to be discontinued now.
Here, check out my awesome earbuds. I love anything with radiohazard symbols, especially bright blue ones. Yeah, this pic is from last Christmas - we're kinda redneck, but not that redneck.