It's true what they say. Sometimes the sum really is greater than the parts. That is certainly the case with the latest release from Palmer Vineyards, a white blend that Spanish-born winemaker Miguel Martin has named "Select Reserve." Retailing for around $25, Palmer Vineyards' 2007 Select Reserve is a blend of 45% chardonnay, 35% pinot blanc, 18% sauvignon blanc and 2% Gew├╝rztraminer. Sometimes, when you taste blends like these, you taste each component grape in a distinct way… almost like tasting each in succession. This wine isn't like that. Sure, you can assume that the chardonnay is responsible for the…