Windows 7 is an impressive and refined OS with fun and productive new features. (In fact, I award it a rare 5-out-of-5 stars in my own review.) But there are some important pieces missing. And while we might debate Microsoft's rationale for not including these solutions in Windows, the truth is, they're easy enough to find and install separately. Best of all, they're free.
Some of these are very useful, I use most of them. (I use Pidgin IM for Messenger.) However the rest are very cool.
Microsoft Security Essentials is now my Anti-Virus of choice. It's free and works just as well as any you can pay for. There are version for Windows XP and both 32 bit and 64 bit Windows 7 & Vista.