So apparently Microsoft came out with a patch to fix the horrendous Outlook 2007 performance problems.
In this article, there is a choice quote from Jessica Arnold, the Outlook program manager:

In the long run, she said the company is “definitely investigating” whether to re-architect Outlook’s use of .PST files for local storage, as some users have requested. But she also warned that users shouldn’t view their active .PST files as long-term storage for e-mail.
“Outlook wasn’t designed to be a file dump; it was meant to be a communications tool,” she said. “There is that fine line, but we don’t necessarily want to optimize the software for people that store their e-mail in the same .PST file for 10 years.”

Umm yea. Nobody would ever store 10 years worth of email would they? And sure no company would ever release a desktop search product that in combination with storing 10 years of email would be extremely useful, would they?
This statement isn’t too far from Bill Gates’ infamous “640K is all we need” comment, but seems to indicate a tendency for Microsoft to underestimate it’s users.
The most infuriating part of the whole thing is, well if we’re not supposed to use PST files, then what are we supposed to use? And I’m going to slap you if you say Local Folders.