Maybe check which apps are consuming cpu cycles when you're not using the phone. Some will run in the background and you don't need them all. Make sure to set the power saving options too.
Do you run a live wallpaper, they really suck the battery down.
The processor clocks down quite low in standby so it's not just that it's 1.4GHz.
Of course it will chew the battery fast if you keep using it.
If you don't need an always on data connection, turn packet data off and see what your email account settings are on. It may be checking for new mail frequently.
Keeping screen brightness down as much as possible helps too.
I rooted mine and deleted some un-needed apps to release more memory and speed it up. If I'm not on it a lot it can go 2 days between charges.
I also have a Garmin Asus a50 which is only 600MHz, it's now used just as a GPS, media player, tool etc, but I don't use it as a phone. It will last ages on standby with 3G and data turned off. Flight mode really extends it.