The equivalent of iSTAT MENUS (system monitoring tool on menu) with Mac to PC?

Download RainMeter.

It has more features than what istat can do.

Performance Monitor works with all versions of windows (except 9x and ME) and is a fair equivalent to what you are after. The built-in task manager utility only shows CPU usage. There are other utilities you can DL as well but I think this is the best.

NetSpeedMonitor is great for monitoring network traffic speeds!

NetSpeedMonitor is a lightweight Network Monitoring Toolbar for your Windows Taskbar designed to be used on computers that run Windows XP, Windows Server 2003, Windows Vista or Windows 7. With NetSpeedMonitor you can monitor the current speed (up- and downstream) of your Network Interfaces and the amount of data transferred.