I was wondering what type of memory is used in PCs.  Is it static or
    dynamic RAM?  For instance:  if I went to a local computer store and
    bought some generic 72-pin SIMMs, would that memory be static or
    dynamic?

PC memory simms are all dynamic ram.

Some PC cache chips are relatively normal (but fast) static ram chips, and
have some of the same pricing and availability advantages of dram simms.

BillW