Getting a Digital Piano

After various months of evaluating, I have decided that I will get a Digital Piano instead. However, I still hope to own a grand one day. Main reason for going towards the Digital Piano route is because I stay in a HDB, I don't have a sound proof room, I can only practice at night during weekdays after work, and I don't want to disturb my hubby when he is reading his books, and disturb my neighbours. Imagine me playing and replaying the same song, part of the song, practising the scales & apreggios 4 - 5 hrs a day. Well, I think I should not disturb the peace and quiet.

Moreover, I intend to pass down this piano to my kids when they are at their learning age. Imagine one kid playing on the piano and the other trying to study. And imagine one kid practice after another, and then my turn. While, others just need some rest, some peace to study or read books.

Also, the lighter weight of the digital piano also makes moving the piano easier. As kids grow up, furnitures will need to shift/re-arrange to accomodate for each other and to create more space and so on. Moving an acoustic piano is difficult coz it is heavy, and because it is also important to choose where to place the piano. But I can put the digital piano anywhere.

However, I still hope to own a grand piano one day where we can play on it when we have mastered a song using the digital piano, to learn the techniques that only acoustic pianos have.

As for the digital piano which I am interested are the Yamaha Clavinova series. Because it looks nicer, with a cabinet and a chair that comes with it. Also, it is suppose to have the better actions which imitate that of a grand piano. And I wanted something that is not too expensive, so I am considering either CLP320 and CLP330. The main difference between the 2 models are that the CLP320 is using GH (Graded Hammer) and CLP330 is using GH3 technology. I tried both digital pianos. Actually I cannot feel the difference. But of coz CLP330 looks nicer, with more buttons, and suppose to have better technology that resembles a grand piano. But is like $500 more expensive. Is it worth it?

The difference between the 2 technology are given below.
http://music.yamaha.com/products/highlights/keyboardsAST/8.html