yes i would recommend an external flash / eeprom for most projects , flash is so cheep ( 64mbit = $0.14c usd / per 100 ) and when designing boards , the extra design allows for alot of options for future expansion where a change of chip may be avoided due to code space issues.

putting EVERY serial string external to the PIC has saved me a lot of valuable program space , i have started to construct a library of common words , and phrases need for the project and is loaded into the flash