Most people think that gmail is a good free personal email account but I think it is without doubt the best free corporate hosted email you can have. Once you combine it with google calendar with its mostly reliable mobile SMS meeting reminders and showing free/busy times of participants you get a very effective collaboration tool. Our company has now been on Google Apps for nearly 2 months now and I know at least 2 more which use it without hassles.
Here is what you should do: sign up with Google Apps and if you are just about starting save yourself configuration hassles by also registering the domain name with them. If you already own a domain, the sign up process with guide you to some simple steps on how you can move to google apps. What you end up with is something like this

You get access to online corporate email, shared documents and calendar. And did I mention all for free. Since now your corporate email is now also a google account, you can use gtalk as a corporate IM and not mix your personal and business connections. One thing we did was create an easily importable list of all 60 people in our company which we could then bulk import in the contact list. This enabled address auto complete for all folks. Since gmail already supports pop, some of us continue to use thunderbird but many have shifted to a purely web access. I really like the mobile access and am able to check my corporate email on the move, get meeting reminders by sms and use shared spreadsheets for many shared lists. Corporate mailing list management is also really simple without any limitations.
A year ago I was the primary system administrator of our company and had managed a qmail system. Even if the installation was simpler, I would never do it again. We had been hit by DoS attacks twice when our server simply became unusable. There were times when the mail system would be down and we would not notice for a few hours (thinking its a quiet day
). Imagine if a small bootstrapped company misses even one email from a prospect who is looking to do business with you. What if your back up script fails and you loose most of your email archive. Worst, what if a hacker takes over your server, uses it for spam and ISPs around the world block your IP/domain branding it as a spammer. I don’t mean to scare you but I have lived with these worries for 2 years before finding peace of mind on this count. Not only does this save you time and stress, it allows you to concentrate on things you should be worrying about.