Debatable. Davidson criminally underestimated due to his lack of charisma for my money.
Anyway, as so many have said, Vaas clearly on top if it's a career that's under consideration, but in the last year Sidebottom has been better. Don't feel anyone else has, however - Zaheer Khan's prowess overstated in this respect.
James Franklin more than a little underestimated too, though for totally different reasons to Davidson. Franklin, to date, remains a disappointment to me however - I've always thought he could've done more than he has. New Zealand's lack of Test cricket is one impediment; his injury problems another; but even so, I still find his economy-rates disappointing, often. A bowler you always feel can go to pieces any minute, despite being as dangerous as pretty much anyone most of the time.
Oh, and on that note, been hugely disappointed at the turn Pedro Collins' career has taken since 2005 too. From 2004 onwards, always thought he had the potential to be a damn good Test bowler, but now looks exceedingly unlikely.
Neither Pathan nor Rudra Pratap Singh I particularly rate the chances of amounting to much ITBT.