I hear your Martimus, but here's where I'm coming from: I bought an iPod Classic 40GB for ~$300 or so a few years ago, along with a Sansa e260. The iPod Classic stopped charging / working 3 years ago, and it simply was not worth the cost or the hassle to take my iPod Classic somewhere to get the battery replaced.
My Sansa e260 battery is still working great, but if it stopped working, it's a simple matter of ordering a replacement online, and popping it in when it gets here.
Yes it's a minor thing, but over time minor things become big things, simply because we add unnecessary barriers to ease of maintenance. So to me I'd rather avoid the situation in the first place, and have the option to easily swap out a part myself if I can.
My iPhone 3GS is now suffering the same fate, where the battery lasts for 30-45 minutes. I am not going to pay a 3rd party service to replace the battery, it's not worth it. If it was a user replaceable battery, I'd easily swap it and get so much more use out of it.