hmm, kind of complicated to tell this
i suggest you save the money to buy guildwars2 and ask your friend to join gw2 also

not worth to buy now, i believe many players will missing after 28/8

yup, 28/8 guild wars 2 will release

hmm, Diablo3, the best part is before lv60, and the source of motivation to play it:
1) You can earn some good USD if you get good drops.
2) Lot peoples still playing, especially if you like co-op game.
3) The moment you see some gold items drop on ground, the gamble feeling is addicting.
4) Elites make you hate them so much, you swear to chop them down like veges.