Comparing surface area of oak cubes to volume of wine exposed, the following chart is a rough guideline for cube additions for a five gallon batch of wine...
104 cubes = 3 ounces = 5 gallon barrel effective rate
79 cubes = 2.3 ounces= 10 gallon barrel effective rate
63 cubes = 1.9 ounces = 15 gallon barrel effective rate
52 cubes = 1.5 ounces = 30 gallon barrel effective rate
41 cubes = 1.2 ounces = 60 gallon barrel effective rate
Most wineries will still oak wine in 60-gallon barrels, regardless of whether it's a Cabernet Sauvignon or a Pinot Noir. The type of oak used and contact time changes with the different varietals, however. Since European oaks tend to release their flavors slower than their American counterparts, they are generally the choice for lighter varietals like Pinot Noir.
End Oaking Flavor = Oak Type + Toast Level + Surface Area of Oak vs. Volume of Wine + Time on Oak/Extraction Rate
For home winemaking, if you can afford the time in the carboy, err on the lower side of chip/cube usage and taste test often to determine when the wine hits your flavor level.
Edit: Since there are so many commercial wineries in the world, they make for a great 'test lab' for home winemakers - if you're interested in what type of oak to use with what wine, look at the back of bottles at your local wine shop or check online reviews. The winery's web sites almost always detail specifically what oak and in what time/quantity they used for a particular varietal coming from a particular location.
Here are some examples:
Foxen Vineyards 2008 Santa Maria Valley Pinot Noir - 8 months French Oak
Melville Estates 2007 Pinot Noir Santa Rita Hills - ~8 months French Oak
Gary Farrell 2007 Pinot Noir Russian River Valley - 8 months French Oak
Louis Latour Pinot Noir Pommard 1er Cru - 10-12 months French Oak
Sokol Blosser 2007 Pinot Noir Dundee Hills - 16 months oaking
Chateau Moutin-Rothschild Bordeaux - 23-24 months French Oak
Shafer 2006 One Point Five Cabernet Sauvignon - 20 months (70% French, 30% American)
Wolf Blass 2007 Grey Label Cabernet Sauvignon - 18 months predominately French Oak (remainder American)
Bodegas Catena Zapata 2006 Catena Cabernet Sauvignon - 12 months 80% French/20% American Oak
- Jim