Laptop battery durability

[sKewlBoy]

I have a Acer Travelmate 4002.
When I'm in windows watching a divx movie, with wlan,lan,firewire and cardbus disabled, brightness and performance to its minimum, battery lasts for about 2h.
If I'm programming (which I don't do much in windows), writing reports or something "light" in the same conditions, battery can last up to 3h.
If I'm in linux, I don't really know what to minimize battery usage. I unload usb, ipwireless, lan, even cdrom modules. I shut down all unnecessary services which start on boot. I lower brightness to its minimum. My /proc/acpi/processor/CPU0/throttling has 8 states (maybe that's the normal), if I choose the lowest one (like I think it's the one I pick in windows), it simple freezes.. I mean, only T0 (the highest performance one) and T1 work decently. The other 6 praticly freeze the CPU. So if I have it on T0 or T1, my battery lasts about 1h and a few watching a movie and 1h45 if just coding in the console (without all the X colors burning battery through the monitor pixels...)..
I feel really bad about this, cuz I thought I would understand myself with battery management under linux with all the power to unload modules, disable everything to its minimum so making battery last its max, but I can't.

Any good experiences comparing battery life in Windows vs Linux ?
And which app do you use to watch battery status and calculate time? gkrellm calulation are quite inaccurate for me..

Thank you

[Darknight]

I've had some success with cpu scaling governors and such but it's been quite a while.
You may read http://gentoo-wiki.com/HOWTO_Gentoo_on_laptops#CPU_frequency_scaling which will prime you, should be relatively easy.
EDIT: I monitor with klaptop, but it's inaccurate too.