i use htop its in repos, you can see whats consuming the cpu and whats consuming the memory..never used conky but it gives you graphical details of the running applications

Sometimes wifi kills your battery if the router doesnt support power saving modes. I have Dlink one. When i connect to it my battery drains in few hours. But if i connect to regular router battery lasts ~ 2 - 3 days

hmm, in this theory does ad-hoc from a laptop drains more ?

htop is just htop. It's in the repositories, and can be found on the downloads part of this site.

As for this thread, I tend to have my N900 last one day with a couple of hours of WiFi internet use, around a day and a half with very little use. I use Advanced Interface Switcher instead of WiFi Switcher, but it does the same thing - unloads the wifi driver - when I'm not on wifi, so that helps. I'm on stock battery. Heavy use of constant heavy multitasking/gaming/browsing will eat battery within a few hours. I try not to have too many things eating battery in the background, but *shrug*. I may have some I just don't know about (ones I do know about is SSH server, all the stock stuff, anything Advanced Power and Advanced Interface Switcher uses, shortcutd/proximityd, cl-launcher [I'm not sure how much that does in the background though], and probably a few other things I just don't remember).

This is without the power saving mode for wifi ever set on.

After 29 discharges (> 300 seconds), BatteryEye statistics tells me:
Low use: 3 days 6h 14m
Average use: 1 day 11h 14m
High use: 17 hours 4 minutes.

I am using ~2600 mAh battery-hack.

My 2c:

Last week T-Mobile switched network to new 3G+ generation available in SF Bay Area (3-5MB/sec). I immediately see a boost in battery while N900 idle - http://talk.maemo.org/showthread.php?t=66763 in that day

It jumped from 30h of idle time to more then 50 now. Sometime now I see a full battery bar at night.

The difference between idle and active usage is quite big with me, seems if i don't touch it it might last more than a whole day off the charger somtimes, but with active usage the life might go down to bellow 6 hours, often around 4 and when i'm really out of luck it starts crying after only 2 hours....