It's hard to know whether to compare Steve Ballmer with P. T. Barnum or with the alcoholic persona brought to life by W. C. Fields. John Gruber of Daring Fireball compares him with Grand Moff Tarkin of the original Star Wars film (now episode IV).
In a much longer piece, yesterday, Gruber lays out a compelling argument that Microsoft has entered a phase of long-term decline, whereas Ballmer would have you believe that recent trends in the market are a drop in the bucket when compared with Microsoft's still undeniable dominance of the PC operating system market, as measured by unit sales (counting a netbook the same as a workstation). (Here's Rafe Colburn responding to Gruber.)
But put a roomful of Mac-using journalists and investors in front of him, and even he notices.