I use NewsGator as my aggregator, but I think I'll have to change. The problem is that when RSS posts flow into your system as email items, desktop search for real email becomes much less useful.

For instance, searching your real email archive for words like "schedule" or "deadline" would likely result in a very relevant set of returns. If, though, your RSS reader is integrated in Outlook, that same search will turn up a hundred RSS posts for every real email message to you.

Ironically, you can search within Outlook based on folder structure, but none of the Desktop Search tools allow you to control indexing / searching. So we're back to where we were 5 years ago: One tool for searching your hard-drives, another tool for searching within Outlook.