RPG for PC

I am looking for a good RPG for PC. If you now any, please tell me.

MMO: Guild Wars (if you don't wanna pay for a monthly subscription), World of Warcraft

DnD: Neverwinter Nights (2), Knights of the Old Republic (not online)

RPG: Oblivion (if your PC could play it, not online), Diablo (2)

Knights of the Old Republic is kinda based on a DnD system.  Really interesting.  Based on Star Wars.  

Top 5 PC RPGs on gamerankings.com 

1. Baldur's Gate II (94.2%)
2. The Elder's Scrolls IV: Oblivion (93.1%)
3. Star Wars: Knights of the Old Republic (93.1%)
4. Baldur's Gate (92.5%)
5. World of WarCraft (91.8%)

Bold is what I recommended.

 Hope that helps!