I bought my d80 on ebay from Cameta camera and would recommend them anytime.
There are also other good dealers and some to avoid. I would always look to make sure the dealer is an "authoized dealer" for that make/ product.
That is why I would not buy from J&K even though they have good ratings there, you will get a grey market product without manufacturer warranty.

As for the package deals, I would also avoid them, as Mike said. The package products are not quality items even from the reputable dealers. The word professional can be put on anything. The bags, tripods, flashes, memory cards, etc. etc. are all low quality and you can get quality items for as much as your adding to your main purchase,(the camera),
Just buy the body and a lens if you are sure its a good lens and the one you really want.

Good luck!