Is'nt the Resident Evil series considerd to be action RPG???
that's my favourite choice by far, although KOTOR is a close second
I'm not including the Balder's gate series or NWN series as I consider them as RPG's and not action based
My best RPG's are (not in any order)
BG1-ToSc
BG2-ToB
NwN-Hordes of Underdark
Morrowwind series