Onto the Top 5:
5. Mass Effect 2 (PC, also on 360 & PS3)
Another sequel where the original doesn't make the list but the sequel is ridiculously high up! Mass Effect 1 was good, but was plagued with poor shooting mechanics, a clunky RPG interface and some rather horrible bugs. ME2 fixed all that and then refined the experience to become more of a shooter/RPG hybrid than an RPG with tacked on shooter controls. Guess what? It worked brilliantly.
Rather than focus on weapon customisation and RPG-levelling, the RPG focus was shifted more towards character development and story-telling that helped to bring the player into the Mass Effect universe. The shooting elements were also changed so reloading and ammo conservation now became important. Gone were the numerous bugs that plagued the original. All these aspect, when combined together produced one of the best RPG/shooter hybrids on the market.
The characters were some of the most intriguing seen in a video game. Mordin was brilliant and hilarious, Thane was deep and philosophical with Miranda loyal and ideological (it also helped that Yvonne Strahovski from Chuck was in the game 
). However, summing up these characters in a couple of words doesn't really do them justice. The vast majority of missions were based on the characters as you built your team and new layers were added as you did each mission. Discovering motivations and each characters personal story, as well as managing interactions between crew members were all part of what makes this game so amazing. The main story itself was actually relatively simplistic, but the smaller character stories were what made the game. Mass Effect 3 improved on the mechanics from this game, but I placed it lower because the hub areas, the missions and the characters in ME2 have an extra lavel of polish, thought and refinement that seems to be absent from 3.
Add into the mix that all the decisions you made in ME1 are carried over to ME2 and you get a truly great RPG experience.
Essay Pro