Dust cleaning is a minor issue. In the past when I used D70, if there was dust in CCD, I used the minor lock up and blowed it. The problem can be solved very easily. Furthermore, photoshop has function to deal with this problem if dust is discovered when editing photo. So, dust is no big deal.
However, if you are interested in Nikon and have sufficient budget, I will suggest you to consider D200. Don't buy D80.