You want an i5 laptop with a Blu-Ray for under $600? I think that this is as good as you're going to get:
http
/www.newegg.com/Product/Product.aspx?Item=N82E16834101277
If you want an i5, expect to pay at least another $150+tax. That machine listed there will do everything you want it to and video playback will be awesome because of the HD 6620G IGP. If you want to have this as a portable blu-ray player for a 1080p HDTV, then maybe the Blu-Ray player is worth it. Otherwise, it's a waste of time because laptops in that price range do not have the HD screens to make it worth it.
Note: That other site points to Dell's website for the product so you would have been able to trust it but it says that the product is no longer available.