Well here is the wonder of if you should buy blu-ray or DVD...
In all honesty, Blu-ray is exceptional. It offers true High Definition viewing. However with some catches.

catch 1. Is your Television able to show all that detail? (a standard low resolution screen will see no improvement)
catch 2. Is the movie title you purchased been mastered in 1080p? (why do they bother place old video on a blu-ray?)
catch 3. Some movies are not and probably never will be released on this format.
catch 4. The cost is at least double of standard DVD's. (Are you going to watch something more than once?)
catch 5. If you already own a movie in DVD, you  do not need to buy Blu-ray again. (Unless you are a true fan of that film.)

I raced out and bought a Blu-ray player as soon as it hit the sweet spot in price. My recommendation is around $250- $350 AUS.

To conclude; Blu-ray is a future proof product. The amount of detail will survive for the next 50 years. Surely something else will come out, but Blu-ray will stay desirable longer than DVD and the likes of VHS. Simply because... you don't need more detail than the cinema film footage anyway... because all you get is film grain...