On an old Windows laptop, I always had to use the hardware switch to force it to use the wired internet connection, otherwise it would try to connect to wireless, and either fail or get poor speeds, and then not discover that it was also plugged in. Though this is what my friends told me they did, I couldn't shake the feeling that this isn't what the wireless hardware switch was designed for.
On my newer Windows 7 machine, I don't seem to have this problem. It did get me thinking, though: does/can Windows send some packets through the wireless connection for increased speed when I am also connected through a wired Ethernet cable?