Note: I will mention Rhone varietals so here is the short list Reds: Syrah (Shiraz in Australia), Petite Sirah, Grenache (Garnacha in Spain), and Mourvedre. The whites are: Marsanne, Rousanne, and Viognier. The long list is somewhere in the high twenties.
What put Paso Robles on the wine map was a group of winemakers who called themselves the Rhone Rangers. They found that Paso was well suited to grow Rhone varietals into amazing wines. Paso also has good Cabs, Merlots, and Zinfandels at lower prices than Napa and Sonoma.
The wineries also make a large amount of Late Harvest Zinfandels. I have never been a big fan of LHZs, mostly because the wineries usually like to call them Ports and they usually aren't either the style of California Ports (e.g. Charbay or Ficklin) or true Portuguese Ports. They are also often too sweet for me, but to each their own.
