One thing to note is the use of DVD regions (see here). In essence, DVD videos are set to work only in particular regions - this was done so distributors could control global releases. You can change the region on your machine but can do so only 5 times. And, as you've probably guessed, the US and the UK are in different regions (1 and 2 respectively). This is only an issue if you play DVDs and intend to purchase DVDs in the UK while still watching your American produced ones.