PIC16F88, PIC16F819 are nices and have internal OSC, which gives you 2 free i/o (or 3 if you don't use MLCR).

2-3 i/o for free, is a real nice bonus.

If you don't need anything timing critical (serial comm or else), no external OSC is also
1) time saver
2) cost saver
3) PCB space saver


come on... forget the stone-age and almost 10 years outdated 16F84