I will use external code memory with the chip. What do you think?

Hallo Ehigie,

if you use an external memory, then you need an EPROM programmer, very probably. If you use a FLASH micro with internal code memory, means something like 89C51, on the other hand, then you need to program your micro. The latest 89C51s are serial programmable, means you can program them directly from your PC, without needing a costly programmer. Make a search at websites of ATMEL or PHILIPS, and here in the archive, of course. Search for 'ISP' or 'IAP', for instance.

I would choose a micro with internal code memory, because then your board becomes tiny.

Good luck,
Kai