If you need digital logic functionality in your design. CPLDs for simple digital logic, then FPGA or ASIC. The choice between FPGA and ASIC depends on the chip volume and application. Millions of chips, that will be ASIC. If application can change in the near future, FPGA. Lowee volume, FPGA. Speed, power, gatecount will also be a consideration.
What are the most common uses for FPGA today?