Hmmm. I definitely think that all of the MOR post-grunge bands--from Matchbox 20 to Third Eye Blind--will eventually get in. What you're going to see, sooner rather than later, is a dearth of popular bands who are worthy of joining the Hall. My hope is that we start to see the incredible indie acts of the past twenty-plus years get their due: Grandaddy, Pavement, Neutral Milk Hotel, Sleater-Kinney, etc. I would definitely rather see them on stage than Nickelback, Creed, or any of the other nu-grunge monstrosities of the late 90's/early 2000's. You'll also see bands like Oasis and Blur make it.
As far as first year eligibility? Coldplay, Eminem, White Stripes, The Strokes.