I think now would be a good time, as console sales are starting to pick up people are looking to the end of the year and the near future. So for these people it would be useful especially since it would give you time to perfect it over the coming month before the price cut comes into effect (Supposidly) In september.
For the new list - definately list the games that aren't going to make 2008 that are already listed, the ones that are bumped into the next year. Also list the games like Alan Wake which are believed to be released next year as well. May as well start with just the big games and add any lesser ones as time/motivation strikes you.
You should list it by Genre and distinguish PC/360 games from full exclusives with a colour code. You could also do the same for believed timed exclusives that way people will have less to complain about. In addition to this, you should list and update as the news changes the 10 biggest games coming up with their box art if available, like you did this year at my request! xD
Tease.
