Is there any speed atvantage to having a primary key type a number (int) over a (varchar)?
There may be a slight difference in favour of the integer, but in the larger picture with network latency coming into the play, any such difference is likely to be negligible. If you want to know for sure, you have to measure.
which is the easiest way to create a primary key
Actually, an auto-incremented integer is not necessarily the easiest way to create a primary key. For example, the easiest way to create a primary key for a table of user accounts uniquely identified by user name is to... use the user name as the primary key. On the other hand, I would prefer to use an auto-incremented user id as such an arbitrary primary key will not be affected by changes to the record, thus changes to the record will not need to be propagated. It is also arguably easier to manipulate in other ways, e.g., if you need to use it in the query string, or in an SQL query, since it need not be escaped.
