It's actually quite a bit different from the one before, death180.. And not just it's size. It's meant to be quicker, there's a lot more HD space, it's compatible with more HD's so you can upgrade yourself, it's a lot better than the old version.
I just got myself the new slim xbox, its very nice, one of the new features is the touch buttons like on the big PS3's, that is quite cool.
slimmer adapter and very quiet too 🙂
side note, the old xbox hard drives are compatible I seen videos on you tube for it, it just means that if you want a bigger hard drive once you put it in (the slim 4gb ones) that is very difficult to take out so make sure you put a big hard drive in otherwise you may fuck up you hard drive lol.