I think the XMB is better than the current revision of the Xbox dashboard.
The old blades one was better than all though, imo.
Dead nation is good, as is PAIN.
Not wanting to stray back OT too much again, but I think XMB is great, well structured/organised and even looks decidedly slick. I havent really paid much attention to the Xbox dash whenever Ive used it but its obviously geared more towards your profile and such whereas PS3 has the home entertainment side with iplayer, TV, BD playback, they are different breeds of machine though and have different menu requirements IMO. Ill be trying out the BD playback for the first time this weekend, exciting stuff for me!
I was going to add Time Crisis to my original list but then realised you would need the gun.
Ive bought Uncharted 2 second hand and I think Ill be alternating between that and GT5 for a while. So what future exclusives are due out that we know of other than Killzone 3 and LBP2? I think there might be a new Dead Nation game coming as well.