Ok, so I finished All routes of Tsukihime, hoping to easly separate the canon events from each route, but apparently I failed miserably.
I'll just list what I think it's canon, and it'd be nice if you guys add things to the list(or deny the already listed ones if they are wrong) before sagebombing the thread.

Anyway, here's the list:
-Arcueid's route, pretty much everything is canon.
-Shiki is currently alive with 50% if Akiha's power, before killing SHIKI, half of that 50% was being stolen.
He kills Sacchin, Nero, and Roa.
-Kohaku was raped, and wants the Tohno blood to disappear, she took care of SHIKI and then released him so that he would kill Makihisa and then set the stage to have both him and Akiha kill each other. She also gives Shiki the ribbon before he went to the Arimas.
Hisui...she is just there to be moe, Shiki gives her the ribbon thinking that it was actually her who watched from the window.
Akiha transfers to Shiki's school, and hates Ciel for no apparent reason.
Ciel is inmortal as long as Roa lives.
Sacchin becomes a vampire and gets killed.

That's pretty much all I could figure out, there are certain things I'll still have to look into, such as Shiki fucking all the harem or just Arcueid, and getting Arcueid in the dream, or Kohaku giving Shiki the Nanaya¡s knife in purpose to cause "mess" or cleaning the bloody clothes in secret after taking him from the park when he killed Arcueid, or Roa's real look...yeah, I have a lot of stuff to look into.