I usually wait a week on any big firmware release. There's always something to worry about... I did however brand my new slim (yes I have 3 PS3s now) with 3.0 just to see it. I plan on doing a huge 400 gig back up and update to the slim with my current data when the fallout is over and I update my current OS. I love the slim so far (kids are getting it so I can put one of these 60 gig BC units up for safe keeping). I put a 500 gig HD on the slim, works great... It was a lot easier to install the HD on the slim too.
PS3 resurgance by GOW3 - Check! Mass Effect for PS3 - Check! Diablo 3 for consoles? I say "For sure"!