There's been a lot of good discussion on this thread, but I thought I'd just add my $0.02 from my perspective as another seller...
On the surface, 6% seems high in this market given that we're close to the end of the year, so not as many people are listing their homes for sale. Logically this kinda makes you think (as a seller) that real estate agents should be hungry for your business and willing to take a lower commission on the sale. Plus you keep hearing in the news that "home sales" are down - but when you really look at the numbers compared to last year, the number of houses for sale is about the same in a lot of areas, it's just taking a lot longer to sell those homes. That's really scary for us sellers!
So when I really started to think about it (i.e. interviewing agents myself)- I started to think that the 6% (or 3% that the listing agent gets) could be very much worth it. Let's face it, regardless of the number of listings on the market, properties aren't selling as fast as they used to. So if I'm going to put in all the effort required to prepare my house for sale in this challenging market, I want the best possible representation for my house on the selling side. I want an agent with great marketing and negotiation skills and I EXPECT them to work hard to sell my home. The average listing in my neighborhood takes about 2 months to sell, and I want my agent to sell my house in less than the average time!
Either way, I think it's good to think about what your 6% is buying you... You want to be sure that you get what you're paying for! For me, this means assurance of a strong internet presence for my home, exposure to the right mix of agents/brokers, and most importantly a good strategy for pricing my home. When I met with the agent I eventually decided to sign with, I contemplated trying to negotiate her fee - but honestly, if she does everything she promises to do to help me prepare, stage, and market my home, she will definitely be worth every penny!
On the surface, 6% of my home's selling price sounds like a lot of money. But for me - selling my home is a huge deal and I'm willing to pay the right person to make sure the job is done right, the first time... Anyway, I hope you find someone that you feel really good about working with, at a commission rate that you feel is fair.
Best of luck! I know this is a scary time to list your house!!!