Well just to tell you my personal point of view:
I'm an ego type of assassin. I want as much buffs as I can get. So I don't really support this "shove those buffs up the rangers' asses cus they are so uberpwnage"-attitude. Rangers are not unbeatable at the top of the parse, not at all. You just need some buff-loving from your group. So make sure no-one tells you you're the last in the line to get buffs. You're TOP DPS, make sure you get the support you deserve! I mean don't bitch for buffs, but there are loads of group buffs you can benefit from, withot taking it away from anyone else. And if you've got an illu, there should be no question that you get haste. If you've got a coercer, no way you don't get a DPS buff.
As far as I can tell autoattack is more important for rangers and rogues than for us assassins. I don't say it's NOT important for us, but I think it makes a bigger portion of DPS for them. I don't play a ranger and only have a lvl 50 brigand, so correct me if I'm wrong, please. So, a haste and DPS buff might be better on a ranger or a rogue but we certainly benefit from it as well. I don't know about double attack, why shouldn't we benefit from it? As far as I know we're the only scout class that doesn't have double attack at all from AAs?
Best thing to avoid losing buffs to a ranger or rogue: Don't be in the same group as they are. Try to be in OT group or MT group if you've got a berserker tanking (always prefer the bers to be with you to the guardian). It's really all about group setup. I usually< end up in a group that's usually melee DPS but can act as an OT group if needed as well.
I don't know what the buffs names are, but as far as I can remember without logging into the game there are:
Dirge:
+all crits 7.5% (group)
+dps (group)
+melleeskills (group)
+str etc (group)
cacophony
Illusionist:
+haste (single)
+double attack 25% (single)
short term int buff (group)
short term fast reuse and cast (group)
...
Fury:
+int and power (single)
agitate (single) yay! ;)
Berserker:
+str
rage (?)
...
Inquisitor:
fanatism
...
Templar:
+str and wis (single)
Coercer:
+dps (single)
Warden:
+melleskills (single)
Defiler/Mystic:
Symbol of Alacrity (short time buff for faster refresh AA)
...
Troub:
+double attack +10% (group)
--> don't know the other ones cus I rarely have a troub
I'm sure i forgot quite a few things, but I'm not logged in and just came home from being out ;). So feel free to add things (and spellnames).
Selfbuffed I have 27ish haste (belt adorn and cloak) and 85ish dps (mostly adornments and selfbuff).
Hope this is not too confusing and nothing is pure bullshit, you understand my weird english and I got all the names right (this time)

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Dai