There is a lot to be said for collecting a variety of different coins. More history, different designs, different designers, collect what appeals to you. There is also something to be said for collecting and specializing in a series including having a finite goal. If you collect by variety, it adds an additional challenge. varieties are often subtle and there is a sense of accomplishment when or if you find a new one. Either way is fine - why not do both?
As far as the Virginia half pence goes, I believe it would be very difficult to determine a variety on a well worn coin. There are loads of mint state examples for that, some rarer that other and some that you will never likely find - at least with a reasonable price tag. The history of the coin is very interesting.