We have bought 2 houses privately and sold 2 house privately.
I would sell it on your own if your house is a gem that is extremely well maintained and makes a good impression when shown to people. If on the other hand your house if a little rough around the edges and has some issues you are aware of I would tend to use and agent.
Here is why:
We sold our townhouse last fall. It was very well maintained and nicely decorated. It had features that made it stand out from other in the area. It was truely a gem. We sold it in 2 weeks for $10,000 more that an agent wanted to list the house at and $5000 more than our asking price. At our 2nd open house we had 5 people calling wanting to make and offer. We were shocked and worried about how to deal with multiple offers and not get ourselves in a legal mess. We really liked the 1st couple to come to formally make an offer (you do not want to get involved with poeple you precieve to be a pain in the ass). They offered us $5000 below asking. We told them there are 4 more offers coming and this offer has to be their best or they might loose the house. My wife and I went off to the side and came back with a proposal. We told them that we would prefer not to deal with mulitple offers. We told them that if they would rais their offer by $10000 ($5000 more than our asking), that we would sign the aggreement and not even look at other offers. They went for it and the house was sold. We were confident about the house and got top dollar and feel everyone is happy.
The other house we sold was my Father in law's house after he past away. It was a house in need of major updates and had not been kept up very well. I spent 3 months stripping wall paper, painting, updating a powder room and the kitchen (new counter, sink and range hood). We also found cracks in foundation which we had fixed. It was the opinion of some that the foundation needed major work not just sealing the cracks. When it was ready for showing it looked like a freshly painted old house in need of updating. It was not a gem!!!! I did not feel good about the house and felt I was selling a house I myself would not want to touch. Not a good feeling. We were honest about the foundation with people looking and in the end it took over 13 months to sell. We were able to sell it without legal warranty because it was an estate sale and we never lived in it. Would I do that one again without and agent. No way......