These aren't top tips, they're personal opinions.
No, they ARE top tips. I'm not going to bore with with if/why/what executes what by default and renders X without asking, but I manage a large corporate network supporting 50,000 (l)users. The majority use Lookout (sorry Outlook) and are locked down so they can't break anything no matter what they click, but a substantial number of mobile users who aren't connected to Exchange use standard POP/IMAP clients like OE and TB on laptops with admin access (so fairly akin to the average home user). The helpdesk calls related to infections from OE users when compared to TB users stands at 9:1. So don't tell me it's just a personal opinion; it's a fact.
Microsoft have traditionally put security way down the priority list. They're changing, thank God, but in a lot of instances (eg. Windows) they've gone so far down a particular road it makes it impossible to turn back. The Windows model of monolithic kernel and every single service running with system privileges is pure stupidity in the internet era... but as we know that's not the environment it was designed to run in. They can't go back; the break in backwards compatibility would kill their biggest customers. Apple were damn lucky to have got away with completely trashing their OS and moving to BSD; but due to the sheer size of MS they could never consider such an option. Windows 7, as it's known, it alleged to introduce big changes and break backwards compatibility. If that's true, they could fundamentally change Windows and make it something suitable for the internet age. But if they get it wrong, it could bury them.
Noone's perfect, but Firefox and Thunderbird are an infinitely better choice for general web and email than the Microsoft offerings.