I think from a Developers POV, the practicality of having a minimum 20GB HDD and the use of BluRay, allows for much more detailed games and faster loading imes, etc. Whilst on the 360 not every user has a HDD and is limited to a standard DVD, so unless the games are toned down abit, or are released on multiple discs they the 360 will miss out on the larger games,; the only other way would be to release a 360 game that requires a HDD for installation but it just means that only a select few would be able to use it??
I think Gears was almost at the peak of the 360 potential, whilst games of similar quality are only just being started on the PS3. PS3 has so much more too go and i think in 08 and especially from '09 and onwards we will really start to see the gap emerge.
There are a few games I am waiting for a long time:
Spore- First game where you create life from a cellular phase to a creature you can control and eat other creatures to gain experience to evolve to a high state.
Little Big Planet- this game seems fun to play and it has co-op with three players you can play with. You can make your puzzle levels. Looks great to get.
Disgaea 3- A Japanese RPG game where the levels beyond 99. It's a type of Final fantasy tactics game, sorta like playing chess. It has downloadable content to get more characters. Hopefully this game will have wireless play to play eachother in a battlemap.
PS3 Home- I'm been waiting for this online game since Sony shown this game from E3. It's free, not a RPG game but as a avatar game. I like to show everyone my apartment and my music and movies collection. Can't wait to get it.