USE AT89S52.
Reason:
1)MISO,MOSI,SCK inbuild feature
2)easy programming
3)cheap
Actually, the AT89S52 SPI interface is intend for programming the device (ISP), not as a general SPI interface.
If the MISO,MOSI and SCK lines can be utilized as a general purpose SPI interface, it is certainly not well supported as neither the device datasheet nor any appnotes specify the registers or proper procedure to configure it as such.
There are numerous other microcontroller which offer a general purpose SPI peripheral module, including many 8051 variants, AVR, PIC and ARM microcontrollers.
The question that should be asked is which family of microcontrollers are you most familiar and comfortable programming?
The answer to the above question is what you should largely base your choice on.
Of course, another point to consider is availability in your locale, which can certainly limit your choice in some situations.
BigDog