Batman is definately worth getting on Blu Ray, anything with quite frantic action looks good, I've got Death Race as well which turned out well and Wolverine. Any animated film with some good colour should suffice, Up is a great film to watch anyway and I've got to admit I enjoy Finding Nemo. Remember watching that on my 28" flat screen when it first came out on DVD and was blown away by the quality then. And I got the original Transformers on Blu Ray, even a 25 year old animated movie looks pretty crisp!
As for Stealth, when that came free with my PS3 I gave it a go and considering I can only ever remember turning off 3 films in my life that got switched off then the disc got destroyed to stop me from ever having to watch it again, awful film, in my opinion anyway.