Jayke asked about Huckleberry. He's great. He is a purebred Aussie, but I think he may not be your usual Aussie. I'm not sure. I've never known any others. His mom was agility bred but she and his dad, who is working bred, both work on a ranch south of here.
Huckleberry is pretty lazy at times, but when he needs to get out, he NEEDS to get out. He runs full out several times a day, and gets cagey and whiny if I try to keep him in when he's bored. He could never be happy as a city dog, but he's perfect for us. Not too crazy hyper at all. I met a border collie last weekend who was NUTS. Totally and completely focused on running back and forth between us and the cows, us and the cows, the hay and the cows, the hay and the cows, then to the llama, who kicked her. I couldn't own a dog like that. But my sister has a lazy border collie. So I guess there are all types.
I used to say I'd never, ever, ever own a herding dog. Now I don't know why it took me so long! I love this dog. He's been very easy to raise and train. Which isn't to say he's totally well behaved. He has a tendency to grab people's hands and sleeves with his mouth. He has a tremendous wiggle-butt (really it's a full body wiggle) when he likes someone, and he loves to poke people in the butt or run between their legs to get attention. But sometimes he really doesn't like people and will give his big bark while backing away from them. I can't figure out why he reacts this way to some people and not others. It has to do with their posture, I think. I know if people ignore him at first he likes them better. Some people who baby-talk him and are too intent on him, he really doesn't want anything to do with. Anyone out there know about dog psychology?
So anyway... If you're looking for a good farm dog an Aussie might be good for you. But I'd definitely make sure you have lots of time for them. For the first several months that I had him, I took him everywhere with me. It's just been this past month or two that I've started leaving him home. They need their people more so than other breeds, from what I've read. I've heard they can have separation anxiety. Huck doesn't have that problem, but he has our other dogs for company and he sure is glad to see us when we get back.
If you live in the city or are gone most of the day, I would definitely not recommend an Aussie. It wouldn't be fair to the dog at all. And if you don't have time for basic training, or to supervise them when they're outside around livestock, it would be a bad idea. A bad herding dog is really hard to find a home for.
So there's my rambling expert opinion - me being an expert owner of one (possibly abnormal) Australian Shepherd. Aren't I a help?