Well, with 1 GB it costs 149 euros per year. Still not cheap, but at least you can now get iDisk sizes where Apple's backup program could actually make sense. The earlier 100 MB was rather ridiculous — and now even with the standard account for 99 euros you at least have 250 MB that can be freely distributed between Mail and iDisk.
Still, I prefer to stick with my own server. It would be nice if Apple gave .Mac an open interface so you could use the .Mac tools with your private server. Because some functions are quite limited — especially in the iLive program suite.
At MacGuardians you can find the original article.