I have had a .mac account for a good few years now and I really dont mind it, I have a family account, my parents and partner all have macs, My email has been converted as well, so sending a mail to my address and using .me.com instead of .mac.com works perfectly well.
I just like the way that everything can sync between systems and online. It is something very simple but works very well. I use the iDisk with work all the time, companies normally dissallow USB ports, so I log on using my .mac - soon to be .me and upload / download files there. Makes it all nice and easy. I would suggest anyone with a Mac and iPhone get yourself a .me account.
I've got a me.com address too now.. what I'm interested in is... will they drop the £68.99 renewal (due 30th July) to the £59 box price of mobile me? I hope so. As for functionality, I am looking forward to getting exchange calendar sync on Leopard via Mobile Me and iPhone (via wifi and cisco vpn of course!). The real thing won't be in OS X until 10.6. It'll be nice to be able to mail photos direct to gallery from the phone, and to be able to sync without docking.. Not totally convinced that mobile me's push mail will be any more 'push' than the IMAP is at the moment.. but that's ok, I'd rather have better battery life than be constantly online. I'm not a crackberry addict. If they do the push thing without killing the battery, then so much the better.
Back to my mac is pretty much useless to me as it doesn't play nicely with other VPN software, and needs firewall ports opening.