The Paso Robles area in California is best known for Rhone varietals. Second to that is probably Zinfandel which they also do exceptionally well. With some notable exceptions Bordeaux and Burgundy varietals don't seem to fare quite as well there, by and large.
Carmody Mcknight is without question one of the notable exceptions. Their work with 100% Estate, 100 % Varietal wines is exceptional. Cabernet, Chardonnay, Pinot Noir, Cabernet Franc, they make them all well.
Their Merlot is particularly good. What shines about it from year to year is that it tastes like Merlot. Not the swill that often passes for Merlot but actual Merlot. Shocking isn't it?
The 2003 Carmody Mcknight Merlot is outstanding. It starts off with an immense nose of bright cherry fruit. The first sip reveals that the cherry notes are actually deeper 
than they smell. The mid plate brings white pepper that hangs through a noticeably long finish. In addition to the white pepper the finish brings with it some earthiness in the way of mushroom character as well as chocolate notes. All of this is balanced by a firm acidity that keep things well in check. This wine screams for some grilled food to accompany it.
Carmody Mcknight does make some blends in addition to their varietal wines. They are also quite good. But in letting the grapes from each variety speak for themselves each year they are providing quite a service. Tasting their wine year after year you get a sense of their Terroir. Their vineyards are renowned for limestone rich soils. That comes through in the consistency of their wines and the refinement they display vintage after vintage.
At $22 their Merlot is not the least expensive you'll drink. However it will be one of the most consistent year in and year out both in quality and varietal correctness.