When we sold our house, I had the same thought but my agent greatly discouraged me. I did learn some tricks from the pro however. Each shot he took was a seven exposure HDR, this allowed him to balance the lighting (and he minimized the uglier effects of HDR). Most of the shots were at about 16 mm, and he did use two strobes to fill the darker corners of the rooms. They came out great, and the realtor did use some photos I had taken of our yard in the spring and fall when the gardens are more colorful. The house sold in 24 hours slightly above our asking price, so the photography may not have even been necessary, but I was satisfied.