Cabernet Sauvignon gives wines of a very different character than those made from Pinot Noir. This is because of the structure of the grape. Cabernet is a grape with smaller berries and a much thicker skin than Pinot. Since the color and tannin are found in the skin, wines made from Cabernet are deeply colored and have comparatively firmer tannins. The grapes are also less susceptible to rot. 
Merlot is a common grape for blending with Cabernet that has only risen to prominence as a lead player in its own right in the last fifteen years or so. It buds and ripens more quickly and easily than Cabernet and has a thinner skin. This means that the wines are forward and fruit driven, with higher alcohol, but less tannin and acid to balance the fruit. The acidity drops precipitously at the end of the ripening cycle. The grape can also be prone to rot, although the bunches are fairly loose.
Within v. vinifera, there is a great diversity of varieties. One of the most interesting is Pinot Noir, which produces some of the most seductive and enchanting wines in the world. The grape is inconsistent, however, and the wines can vary from rich and full bodied, well-oaked styles to thin, sour pink wine. The main fruit aromas include cherry, raspberry, strawberry and plum jam. As the wine matures, it can show baked red fruits, violets, game, rotten vegetables and truffles. 
Grenache is the backbone of the wines of the southern Rhone valley, and the second-most widely planted black variety in the world. This grape originated in Spain, where it's called Garnacha, and was brought to France in the eighth century. It is a thin-skinned grape with loose bunches that ripens late and is prone to oxidation. When it ripens to very high sugar levels it produces high-alcohol wines with high sugar, low acid (oxidizing easily) and light color. When grown in higher elevation, cool climate vineyards, as in Sardinia (where the grape is known as Cannonau) and some regions of Spain and France, the wines can show low sugar, low alcohol, fresh berry fruit and vibrant acidity. The aroma is typically expressive red berry fruit with herbal, spicy and peppery notes.
The most widely planted fine wine variety in Italy is Sangiovese. Several clones exist, including Grosso (Prugnolo, Brunello, Morellino), which is widely planted and ripens earlier than other clones. The Piccolo (Sangioveto) has tighter bunches, smaller grapes. Sangiovese often lacks deep color, and is subject to oxidation. It can produce a wine relatively high in acidity and low in extract, with medium sugar, and medium to high tannins. It has a tart cherry, earthy aroma, and is often blended with Cabernet to give it forward fruit. Sangiovese di Romagna is a separate grape with its own clones. Yield is generally higher, but quality is not necessarily lower. 
Nebbiolo is considered the finest grape of Italy, used in such renowned wines as Barolo, Barbaresco and Gattinara. A difficult grape to grow, it is one of the last to ripen, and it is prone to mutation. The different clones include the Lampia, which gives yield, colour, body and perfume, the Michet which has low yield but gives good structure (thought to be the best clone), and Rose which has a low yield and light body, but gives perfume to the blend. Although it is fairly low in coloring agents (anthocyanins), Nebbiolo is high in tannin.