Resist Buffs etc.

Hi folks,
At level 115, when we have decent gear at this point (I don't have raid gear, just group), have max AA etc., are the standard "old" resist spell buffs worth anything at this point? I mean stuff like Guard or Druzzil (Chanter -- magic), Protection of Seasons (druid -- fire and cold), Talisman of the Tribunal (Sham -- disease and poison), etc.?

Please excuse my ignorance -- if I look at my character info, whether these toons cast these resist buffs on me or not, NOTHING changes on my main character page for the various resists numbers. However, if I then look deeper in the "stats" tab for the character, I do note if I have these resist buffs on, the "GREEN' numbers go up. The white ones do not go up, but again my "TOTAL" does not change whatsoever. I am assuming the difference here is limit threshold issue.

With a ridiculous number of buffs we can have (my friends drop everything including the kitchen sink on me when we are about to engage a named heavy hitter), and every spot is coveted. I am grateful that many buffs now also can go in the song window, alleviating some of the space issues, but as I am a numbers guy, I have always wondered if these resist spell buffs have ANY effect on us (beneficial I mean) in this context or resisting spells -- period, full stop.

Lastly, if I have your attention, for those way more informed than me, why is it that most buffs get overwritten depending on level (I am refereeing to sitting in a lag-pile and people casting MGB buffs), yet the cleric line of spell haste buffs such "benediction of reverence", "benediction of sanctity" etc, all seem to pile up on me? Should it NOT be that the highest one overwrites the older one? If the higher one (reverence which is rated for level 115) and has the same beneficial properties as the lower one, but has a higher max level, why is it I can come back 1 hour later and find both those buffs on me? Yes I can block the older one, or just let my healer merc cast it on me but was just wondering, again cause I am inquisitive.
Cheers.

First, yes, most resist buffs do nothing once you reach your resist "cap".

Second, the reason for the cleric spell haste spells piling up is that they tend to be for different spell levels or percent of haste. Much of this is taken care of starting Torment of Velious, where many buff spells no longer come in different ranks.