What impact has Windows 7 had on the Mac’s sales and market share gains? Not much, according to Joe Wilcox in BetaNews:

Windows 7 did little to slow the Mac’s sales trajectory during fourth quarter, according to NPD. Year over year, Apple doubled US retail unit share—from 5 percent to 10 percent—for PCs selling between $500 and $1,000. More startling, Apple increased its unit share from 79 percent to 90 percent in the market for “premium” PCs, meaning those selling for more than $1,000.

With the iPad, is Apple venturing more strongly in the $500 to $1,000 segment? Yes.