So far, at least. Here's what I just discovered, might be old news already, but I thought I should mention it here, anyways ...
First of all, I'll tell you the reason I have NOT already discovered this :) it's because past year I have become a rather Domino ignorant, due to my job responsability of architecting solutions. And I mean it, it just so happens I realized how much I need to learn in areas like WAS, Portal, RUP, UMF, Rational (ClearCase, ClearQuest, Method Composer) and I could continue... So, Domino is no longer my focus but I am a devoted Domino blog reader and early adopter Domino "new stuff" within IBM.
Back to my just discovered top reason for adopting Notes 8. Or Domino 8.0.1, or, Domino 8.x
The keywords are "unified search". This is enabled in Notes 8 client, as in View\Toolbar\Search. And magically you'll be presented on the right hand with a search field which will search in all of your mail, INCLUDING any archives you have linked from within your current mail database.
How cool is that ?! you can actually now search within ALL your mail, not having to go through each archive at a time using the beautiful Full Index of Notes, however limited on a database only, or calling for help from Google Desktop Search with the Lotus Plugin.
update: seems this is not accurate, afterall. At least on my business computer this does not work anymore. If anyone has more details about this, please let me know. I'm sure though this used to work as I described, however it appears it does no longer work on my Notes 8.0.1 install.