...everyone should be using tunneling and a restrictive firewall for wherever they have any traffic that is in any way sensitive.
For REALLY sensitive information, investigate PGP, additional TCP wrappers, multiple encrypted pipe 'jackets,' (IPv6, with Kerberos authentication to PAM, anyone?) and the use of symmetric versus asymmetric (AKA 'public') key crypto systems, and journaling and encrypting file systems. Given the current Hotmail problem, CR and other issues, it is becoming clear that the ultimate responsibility for security is on the user, since software and service providers have abrogated all responsibility and gotten the Congress Critters and Reptilesentatives to pass laws to allow them to do so (except in Iowa). Too bad, since most users are idiots, and that's why the script kiddiez are always so successful (Well, that and the clueless media and politicians.).
On top of the above, we give the bad guys tremendous strategic and tactical intelligence about our responses and defenses and the efficacy therof. However, because of the iresponsibility of our vendors, service providers and lawmakers, we have no choice.
...and if you thought you were safe inside your network, just because you have no wireless network devices and use switched segmentation? Try this little project. Read it and try not to weep.