I prolly use my phone more than the average user, and just about everything I do with it uses data, so I keep an active data connection pretty much all day.
The ROMs I run the most are MR4 and MR6 and I take my phone off the charger at about 3:30 am and I usually have to plug it in by 10:00am because its down to 20-30%.
But I play Pandora almost constantly while Im at work, to and from work I either browse the net or watch a movie or watch youtube.
And while doing this Im usually IM'ing and texting.
I just figure when you use your PPC as hard as I do, 8 hours is about all you can expect to get outta it.
Oh ya and sometimes when Im in the car I switch out to my Mugen 3000Mah battery, but never take it any where cause its horribly UGLY!