What e-mail client should I use?

Check out Airmail. I use it for my Gmail accounts, and it suits my needs for Gmail.

 

Check out postbox. I've been using it for a year now and I am quite happy with it. Organizes all my gmail and imap accounts like a champ. They also have a version that runs on windows. So you can have a seamless desktop mail experience on both platforms. A big seller for me.

I've tried most of the desktop mail programs and found postbox to be the best for my needs. I believe they have a trial period. It is not free, but most of the good mail clients (and most good software) will cost money.

 

Unibox is quite simple. No spamfilter yet though, but most are easily identified.