The X220 appears to have made it worth to look into the purchase of a new notebook this year.
Yet, telling by my fiancée's W510, the high-pitched noise is definitely an issue that I have to see resolved. Call me exaggerating or, well, still with good ears, but the noise drives me bad within a good 15 minutes.
Does anyone know whether the issue has been resolved with the new Sandybridge platform? Otherwise, I prefer to settle with my T400.
I'm assuming you mean the cooling fan noise? Sandy Bridge CPUs are more efficient than previous generations, but they still need to be cooled. There should be less fan noise, but it won't be eliminated completely.
High pitched noises like that can come from inverters on the LCD panel, power supplies and other stuff. My power supply makes that noise. It usually has to do with the quality of the components, I also believe digital inverters are more likely to make that noise than analog ones.