Sometimes dependency trees and graphs get very complicated, but what I usually care about is either:
A. bugs in my product
B. bugs directly blocking my product
C. bugs blocking bugs blocking bugs in my product
Note that unfortunately in some cases my product might actually be two products (until i dream one of them away), so it needs to be a multiselect.
For the example bug given above,
363154 maj -- PC firstname.lastname@example.org RESO FIXE [TB-3a1] Improper RSS Display After Todays(12/8/06) Auto-update
363276 nor -- All email@example.com RESO FIXE Header bar no longer full-width
363466 maj -- PC firstname.lastname@example.org RESO DUPL RSS preview is 60% narrower than it should be
are not in core, so for option A, they'd be excluded.
If bug 363675 which blocks bug 363154 was not already directly listed as a dependency of bug 300030, then it would be excluded for option B.
Sorry about the example being kinda bad. I don't usually look at dependencies.