You get an incredible selection of lenses. This allows you to go from ultra-wide (single-digit focal lenth) to 1000mm zooms.
To me, the primary advantage of the SLR is that you look through the lens that grabs the image. This was a big deal for film, as a SLR is the only type of camera that you can use a polarizing filter with. But since a digital will let you look through the sensor using the LCD, it is not as big of a deal.
SLR lenses also tend to have better aperatures, you can control the aperature. If this is important to you, then make sure that the digital point-n-shoot has a real mechanical aperature.
So, if you are the type of guy who is happy with a 28-80 stock lens on a SLR, then do not bother with a digital SLR. Just get a nice digi point-n-shoot with a real mechanical aperature and full manual.