I have an ASUS EeePC 701 (Linux) and here are some battery tests that I have done on it.

Test 16 Sep 2008:

07:24am Started wifi, opened browser to Slashdot, switched to battery power.
07:31am Refresh browser.
07:39am Refresh browser.
07:52am Refresh browser.
08:06am Refresh browser.
08:18am Refresh browser, noticed the battery bar is now down to 3 (of 4).
08:28am Refresh browser.
08:47am Refresh browser.
09:03am Refresh browser, battery bar is now down to 2.
09:17am Refresh browser.
09:25am Refresh browser.
09:33am Refresh browser.
09:45am Refresh browser.
09:48am battery bar changed to 1.
09:53am Refresh browser.
10:04am battery bar changed to 0, "Power status: Battery charge is low"
10:06am Refresh browser.
10:11am Refresh browser.
10:16am Refresh browser.
10:21am Popup "Battery charge is very low, and the system will shut down in THREE minutes if it is not plugged in.  Save your work and prepare for the system to shut down."
10:24am Shutting down system... off.

Test 16 Sep 2008:

02:35pm Wifi off.  Switch to battery power. Playing an XViD from 2 gig SD card fullscreen.  
03:20pm Video completes playing.  Battery indicator still on 4 bars.
03:21pm Restart video.
04:07pm Video completes playing.  Battery indicator at 2 bars.
04:08pm Restart video.
04:54pm Video completes playing.  Battery indicator still at 2 bars.
04:56pm Restart video.
05:07pm Switched from full screen.  Battery indicator at 1 bar.  Switched back.
05:18pm Restart video.  Battery indicator still at 1 bar.
05:23pm "Power status: Battery charge is low."
05:41pm Popup "Battery charge is very low, and the system will shut down in THREE minutes if it is not plugged in.  Save your work and prepare for the system to shut down."
05:45pm Shutting down system... off.

Test 17 Sep 2008:

08:18am Wifi on. Switch to battery power.  Playing a google video, 57 mins.
08:41am Screen blanked, pressed shift to turn it back on.
09:04am Screen blanked, pressed shift to turn it back on.
09:08am Battery indicator at 3 bars.
09:16am Selected "play again".
09:36am Screen blanked, pressed shift to turn it back on.
09:46am Battery indicator at 2 bars.
09:58am Screen blanked, pressed shift to turn it back on.
10:15am Selected "play again".
10:29am Battery indicator at 1 bar.
10:42am Screen blanked, pressed shift to turn it back on.
10:48am "Power status: Battery charge is low."
11:04am Popup "Battery charge is very low, and the system will shut down in THREE minutes if it is not plugged in.  Save your work and prepare for the system to shut down."
11:08am Shutting down system... off.