Firefox to browse, as it's the only decent graphical browser that works on OS X, Linux and XP on those rare occassions when I have to use it.

As for email, it's got to be mutt, for several reasons:
1. I can install it on my server, ssh in from anywhere and not have to copy my preferences like I would with say Thunderbird or Outlook (ok you might be able to load them from a server or something, but when you use as many different machines and networks as I do that's not really practical)
2. HTML emails don't load lots of stupid images (they're nearly always spam anyway)
3. I can easily delete loads of obvious spam without having to actually open any of them
4. It runs fast and doesn't leak memory or bring my machine to a crawl ten minutes after opening it
5. When I send emails, I know they're going out in plain text regardless of my preferences (Thunderbird defaults to HTML, or it did last time I checked)

The only problem I've ever come across with mutt is its inability to use an external SMTP server, but there are ways around that and I believe there's a project called Mutt Next Generation or something which does allow for this. Personally I just run a simple postfix server that accepts connections only on 127.0.0.1 and relays everything to my ISP.