Morrowind is a very large, non-linear RPG. Non-Linear meaning that the game has one main quest, and even more other quests for you to do. The enviroment is a Medievel Theme, Very Massize Island (Seriously, its huge) And very well detailed (not perfect, but great for a game this size).
You basically chose your name, race, sex, face and hair, class (pre-defined or custom) and a Star Sign. Then you are relased, given the name of a contact in a nearby city who'll direct you on the main Quest. Levelling up is unique compared to other RPGs, I'd like to try and explain it but its hard to do, you'll figure it out when you play it. Also no Turn Based Fighting, you walk/run/strafe/jump in the fight and attack with your weapon. Weapon types and selection is huge, as is Armour Type an Selection. Magic is very varied too, you can even creat your own spell, or enchant weapons/armours/clothes with magic abilites.
Also for the quess, you can pick up random jobs from townspeople of join a Guild to get Quests, completion will result in Money, Items and maybe Promotion. Promotion will allow you special services for cheaper prices from member in the same guild. There are the Fighters Guild, Mages Guild, Theives Guild, Morag Tong (Assasins), Commona Tong(Gangsters, but you cant join them), The Temple, The Imperial Legion, The Imperial Cult, The Great Houses, Redoran, Hlallou(sp?) an I think theres another house and maybe some more guilds. And the Guild concerned with the main Quest, the Blades.
Theres a new version coming out for it, Morrowind Game of the Year edition. It has all the upgrades the PC version had included with it. Not sure if its available in the UK, but you are much better getting this game, It'll just make it even more larger.
You'll probably get put off this game the first few times you try, remember the game is supposed to take youweeks, maybe months to get any real progress, so be patient. And save often too. Theres also cheats for the Xbox version that are helping em out

Plus ive got the best Long-Sword in the Game, and a Redguard Character with a massive Longsword ability.