I have a Razer DeathAdder mouse and like in your case, the sensitivity/acceleration are too high even if I put them at the lowest level in the mouse preferences. So to solve this problem, I used the xinput command.
First, you will need your mouse ProductName and ID:
xinput list
...
Razer Razer DeathAdder id=8 [slave pointer (2)]
...
Then you set the constant deceleration level that suits your needs with this command:
xinput set-prop 8 "Device Accel Constant Deceleration" 3
# 8 = DEVICE_ID
# 3 = LEVEL (factor) Higher = Slower.
To make the config persistent (and make it system wide), you will need to edit your xorg.conf (/etc/X11/xorg.conf).
Section "InputClass"
Identifier "Razer" # Whatever you want.
MatchProduct "Razer Razer DeathAdder" # Product name from xinput list.
Option "ConstantDeceleration" "3" # The same value as xinput.
EndSection
Once you reboot, you should have the same result as the xinput command.
Let me know if it helps.
Try Pointing Devices
sudo apt-get install gpointing-device-settings
It contains a nice GUI for changing touchpad settings like sensitivity, min/max speeds and palm detection.
Best Answer
What I've found is that deleting the gconf mouse folder resets everything to defaults. The slider bars don't change, must be cached somewhere in gnome.
Using the terminal:
Open a terminal (Ctrl+Alt+T), perform the following command:
rm -fr ~/.gconf/desktop/gnome/peripherals/mouseFrom Nautilus:
Press Ctrl+L
Paste or type
~/.gconf/desktop/gnome/peripheralsOpen context menu (right click of mouse)
Select the option Move to Trash