Am tempted to buy a 360, money is tight so was wondering if the Pro (Premium) is a much better purchase than the Core (Arcade).  I know the pro comes with a HDD.   Based on the fact that I already have an independant media center do I need the additional hard disc element?  What benefits would there to buying the pro over the core.  (cannot stretch to an elite)

Cheers all

Save game, game downloads, game demos, arcade games, coming soon old xbox games, games having options to utilise the hardrive to run better (mass effect for example preloads if it sees you have a hardrive and so less load times) etc
Yes it is worth it and also worth it to see and check the one your getting is a newer one with hdmi

Just get the Premium and dont even wonder about the Arcade.  Youll be wishing you had the HDD after a few months without.

Just looked on Ebay at Xbox HDDs, and the 120gbs are only about £60 now.
May have to get one and relegate my 20gb to my core.

Good job youre not looking at a PS3, youd be more confused!
I am sure I saw a premium this week which was £230 with 2 games...