Touhou 6, 7, and 8 are all fantastic games. I'm not really into the doujin scene apart from the music remixes (and for most the music tracks I actually think they are better in the games). Touhou 6 is pretty brutal (they are all very difficult of course) but I think they are well balanced in difficulty on the whole. You can use continues and start with many lives. I think Touhou 7 is probably the most balanced one. Most accessible too. But I think it's worth playing 6, 7, and 8 in order, because I think it does very cool things with the characters and it is best represented in gameplay: who becomes playable in subsequent entries and who you fight as bosses.