For me, ARPG means I can only control one character to kill monsters or other players, and I can't pause the game for thinking of some ideas. So Baldur's Gate, Neverwinter Night, Dragon Age, Fallout are not including.
No.1 Dracula X
KONAMI insists on that this game is ACT but not ARPG. But actually as ARPG, it's perfect. But as ACT, it's so normal without anything special.
No.2 Ys Series (After Ys6)
Falcom is a small company, but their Ys Series are so great! Although the straight questline limited the freedom of playing, but it's franky style is so good!
No.3 Dark Messiah of Might & Magic
Maybe it's the best First-Person-Kombat game on PC. The Halflife 2 Engine and the Might & Magic background make the whole world with both peaceful and danger. You can enjoy the peaceful life of the farmers, and you can also climb upon the house to kill ghost. You can use arrows and magic, and also you can use your sword to kill your enemies.
No.4 Diablo Series
I don't think I should introduce it anymore. Before 14 years Blizzard created a online mode. Now it's the most important part of most MMORPGs. I love them!
The biggest enemy of Diablo 2. The skills are not complex, just only simple and useful skills will make you satisfied!