VNC is Painfully slow and not secure enough a replacement IMHO.

How do you mean VNC is painfully slow? I'll agree that with a Windows server it's slow -- it's the nature of Windows. With a Linux server it's pretty quick.

Having said that, VNC on Linux is still pretty slow over a cable connection (from work to home -- i.e. the screen updates are going the "wrong" way) -- XP remote desktop is faster.

You could use TightVNC, as Peter suggests, which might help.

Tunnelling it using ssh is a viable option.

I don't want to have to start adding fat clients on my work PC either.

I presume this comment isn't aimed at VNC? The client's exceedingly lightweight.

I'd ask this question, though: why do you need to see your home desktop from work at all? You can get a shell on the remote machine using ssh (use PuTTY as the Windows client), which may be all you need.

If you have to use a graphical application, consider using ssh to forward the X11 connection back to your display at work -- this is relatively easy if both ends are running Linux (or other *nix), but should be possible with judicious application of Cygwin on the Windows end. This violates your "fat" requirement, though.

As for the security, this is easy -- use ssh.