I came across this add-in for outlook the other day after reading through my twitter feed. I had a look at it and downloaded the free version.

Xobni, gives you a really powerful search capacity within outlook and links contacts to attachments and conversation threads. It can also be used to look at the contacts facebook profile.

I get some emails, but not a large amount in the grand scheme of things, and I found this to be really useful when I needed to go back and find attachments that I needed. I also like the way it integrates the facebook profiles as well, so you can keep upto date with your network.

Have a look at www.xobni.com