Here is an excerpt from a previous post in a similar thread. Although now I am running the PR1.3 and the v46 kernel. All other details are the same more of less and I am giving you today's usage.
My setup:

Overclock 500-1000 on ULV. on V40 Kernel. (now v46)
GSM only when not using internet or when accessing internet via wifi.
Battery Indexing Disabled using Tracker-cfg.
Battery is original that I have had since early march.
(I now have swappolube setting loaded also)

Today's use was around 25 sms and 30 minutes calling. Some photos using fcamera, about 80 minutes of Angry Birds. Some internet browsing approx 1 hour (wifi) and the updating of weather and email over wifi or 3G once every hour or so. Around an hour of listening to music. Some Jabber text chat via skype and facebook maybe for 40 minutes over 3G.

Full charge when I left the house at 0730 and I currently have 79% remaining.

Now that is not bad at all. That usage will get me about three days or so before I have to recharge.

Just want to add my battery thread with the option to go with a bigger battery.

Battery Test & Battery Mod

Mine on idle consumes 1% every 2 hours... But when I ran psx4m 20mins = 15%

But hey... I installed 82 third party apps... Mostly devel. And running 4 daemons.

That can be true but it depends on how the battery is stored. What you said is true if the battery is stored fully charged at 25°C, but if it was stored at 40% charge it will have 88% of original capacity after 3 years at 25°C, this capacity loss can be further reduced by storing at cooler temperatures. Read the Wikipedia article for some information on this.

I have nothing wrong with carrying an extra battery, I normally do anyway, I just hate using it cause I don't have a desktop charger, only like 8 bucks on eBay though - should get one.

Mugen battery is ridiculously sized and expensive, plus, the battery cover has some camera issues. As for high cap batteries from third parties, they're rarely even 1320 or 1350 as it is.

Nokia said their goal was one full day of heavy usage, so probably about 10 to 12 hours. As for the overall performance of the battery, it's sad. My friend can get twice as much use out of his EVO 4G than I can and he'll still have 50%ish battery left.

I used to keep Skype active but there's no point since I have to turn off my active T-Mobile connection if I'm not using it, else I'm screwed.

OK, so here's my day with my N900.

Email updates every 30mins, 15mins rss updates, connected to gtalk and skype all day and weather updates every hour.

Unplugged N900 at 8.30am,
idle till about 10.30am, then browsed a little and tried to downloaded a 175mb which crashed.

Took photo, checked phone and email/rss every now and then.till 1pm.

Downloaded 175mb file at around 1pm, then kept checking email/rss/phone every half an hour or so till about 6pm.

Then got a call around 6.45 for about 10mins, then two/three more calls till 9.30pm.

And also browsed the web for about 20mins relisting an ebay item.

Now down to 11% according to lshal - but lshal only reports upto 94%.

Should last me till 12am before starts saying low battery.

It might be just my imagination, but setting swappiness to 30 appears to have helped my battery significantly.