While I don't own one personally I do tend to believe it tilts toward being more of a toy. To start I believe that I read that the number one use for the iPad is playing games. However, as a college student myself i'm still interested in getting one, however, considering that I will primarily use it as an entertainment device the $500+ price tag is pretty steep for me.
I don't think it will replace my laptop at all. However, I can see it replacing my netbook. I find my netbook to be really slow and the keyboard to be quite cramped. For this reason I don't use my netbook for any serious document writing, primarily surfing the net and viewing media. But I actually find my netbook to be slower than my iPhone so I see the ipad as a light weight alternative with a bigger screen than my iPhone and faster than my netbook.
JMO