Personally, I keep most of my contacts in Stikkit (http://stikkit.com). One contact per stikkit and they're searchable, tag-ready, all that stuff. And you can export them as a big address book file and plug them into just about any PIM you like if you decide to use something different.

Oh, and you can email all the contact info to stikkit and it will create the contact for you - very slick!

Good luck