For what it's worth, my n73 has 3 batteries and each of them is flat after 2 days of standby.
YMMV - what I do know by now is that Apple don't go for the bleeding edge, which is what 3G essentially still is. They make bleeding edge products, they just don't seem to use bleeding edge technology.
I think this is so that they can be sure it lives up to their standards which they're known for. Sure, a lot of people are happy to trade off a short battery life or other quality issues for a 3G iPhone or a HDD iTouch, but it's just not Apple, they would usually rather wait until they can deliver the technology *and* the battery life / size / quality / etc.
To be honest, I'd be worried if they did start doing this. If they start offering options of "poorer quality/usability but more features", let's face it most people would go for those (consumers rarely understand what is best for them and instead go for the best "bang per buck" ratio), reducing demand for the higher quality/usability versions. The HQ versions would therefore get pulled off the shelf and those who buy Apple for that reason (the original niche market) would lose out. People who did buy the feature packed versions would subconsciously notice the lack of quality and substandard usability, and Apple would no longer be anything special, just another mass producer of MP3 players and computers with fancy cases.
Just my opinion/theory...