Since at least the configurable hero in "Nightfall", which are still much stronger than the followers in the first two parts of "Prophecies" and "Factions", it is also a great single-player role-playing game. Especially arise incredibly complex "synergy effects" if you have more than one campaign or the extension "Eye of the North"; you can work with any heroes from each campaign from a certain time, typically with level 10 or when you reach the respective capital, go to the other continents. This can also be the "Prophecies" - the hero (instead of just followers) and give "Factions" -Charakteren. In particular Prophecies becomes easier.
Also one must possess for the extension "Eye of the North" with only the first character level 20, the other on the same account can then sooner in the north.
Thus, - in extreme cases, in possession of all the 3 campaigns and the expansion - each character a plethora of quests to choose from. The great thing is that it is always possible for Guild Wars in general, useful and profitable to play in "hochleveligen" or lower areas, even if you are in groups with large level differences; eg as a Level 8 with a friend Level 20 (plus respective hero) it is still playing meaningful because there are for each advantages: Not only leveling up, but also the other continents tour (in which one is not even become Level 20) find there directly controllable new outposts, uncover the card and heroes and quest givers etc.
Most of all motivated - even more than the oft-cited "Item-Hatz" for rare items - Guild Wars activation always new skills (skills) that always allows new combinations for the 8 simultaneously usable. The skills can be bought not only in towns with crafts dealers, but also captured monsters and unlocked as quest rewards. Even after 150 hours of play as a necromancer monk one looks forward as huge as a child, when you as a quest reward with Level 8 receives four new skills with an Assassin-ritualists and gets additional attribute points.
There are always test accounts on the official website, in games magazines and games sites. So even without PvP: clear recommendation!