If cutting round blanks, a 3/8" wide blade (or 1/2" at a push) would help with cutting round bowl blanks etc. The experts suggest you adjust the number of teeth on the blade to the thickness of wood you are cutting and aim for three teeth in contact so for anything thicker than 1" a 3 or 4 tpi skip tooth blade is probably where you want to be. I have also used the M42 blades in the past and agree they are worth the extra expense. With a normal blade, if you hit a nail the blade is kaput but with M42, it will cut through with minimal loss of sharpness and will still be usable, probably for a considerable time!
Whilst is best to have the correct blade for the intended job you can get away without having to change the blade if you take it slowly. This is a 12" (300mm) cut with a 6 TPI blade.
Again to illustrate the wrong blade, this afternoon I was cutting up a 4" post, the maximum my little Scheppach bandsaw will take, with a 6 TPI blade & the wood was moving so slowly that it was only noticeable by looking at the end of the wood as it moved over the table - but still quicker than doing it by hand.
Like the others mentioned a 3/8'' 3tpi is a good all round blade. You dont really have to make round blanks either just knock off the corners. I probably do more blanks with the chainsaw than the bandsaw anyhow. A couple of times cutting green wood (on the bandsaw ) I have ended up with the blade, the guides and tyres all gunked up with the sap. It dries hard and a real chore to clean off.