Since the latest (and last) Harry Potter movie is still showing in cinemas it might be almost premature to be thinking about boxsets .. However it's 2011, so we can pre-order DVDs and BluRay as soon as we get out of the cinema..
Here's a particularly nice Harry Potter boxset (currently only available via Amazon France):
The boxset contains 11 bluray discs in total, which is made up of the 8 films of the series plus 3 discs of "extras". If you haven't switched to bluray yet you can get a DVD version as well
- Largo Winch 2 Boxset (films.ie)