I only use either 4MHz or 20MHz, 4MHz is very handy because it gives 1uS per instruction - and a lot of the processors I have are only rated at 4MHz (although most seem happy to work at 20MHz at well). This is usually plenty fast enough, you normally spend most of your time slowing things down, or waiting for things. I also like to use the internal oscillators whenever possible, it makes life much easier if you can dump the crystal and gain a couple of extra pins :lol: