I like in the following order:

new aluminum Trackpad

The animal Mice (they are sooo cute)

Logitech Mice

G.E. Generic Mouse

Trackballs (Logitech/Kensington/etc...)

Apple Mighty Mouse

Ones I like least:

Crappy Ball Mice

Apple "HockeyPuck" mouse

Apple ADB Mice

TrackStiks (IBM/Whatever)

Those little things that are bars that you push up/down/left/right and aren't really mice)

Trackpads that have tap support. They suck since it's the main default type. You have to install a drive to turn it off, and then the driver likes to disable side-scrolling, or disable it in some apps)