Yeah I will join this club of unhappy people.
I own 2 x iPhones, 2 x iPads and a Mac Book Pro.
Started with iPod years ago and signed up for iTunes with an email address of choice at the time (boy, did I wish I'd thought more about that), since then I've purchased approximately 7 years worth of music etc on that email address.
A few years back I migrated to Mobile Me in a bid to keep, my contacts and calendar in particular in sync, so at that point I get @me.com address
I'd been using original for iTunes / iPad / iPhone purchases and @me.com for Mobile Me mail, contacts and calendar.
I booked a genius appointment taking in several thousand £'s worth of devices into store to get help with this only to be told be a smug spotty youth that I cannot merge Id's - did I hear you right son, the best technology company company in the world cannot get merge my two IDs together!!!!!! Trip wasted of course.
And here we are now, got my iOS5 eventually last night, upgraded my Mac Book and iTunes, ended up in all sorted of hassles about which is primary Id and which isn't. Just absolutely unnecessary rubbish Apple. Come on - get this sorted !
I followed the mobile me migration instructions and setup @me.com as my iCloud account then went into Store Settings on my iPhone and signed out and in with my old email address that's been used in iTunes then I get a "This device is already associated with an apple ID and auto download will only work with 1 id every 90 days"
What I find amazing really, unless I misunderstood this, is Apple is actually creating a bigger problem here by suggesting everyone takes a free @me.com address with iCloud, surely all these people already have an iTunes login, effectively creating the same situation we are already in.
We can push data all over the place through all our devices, but we cannot get the content bought over years from 1 ID merged into another ID. Rediculous!!!
I wonder if iTunes Match (if it gets to UK) will fix this eventually once and for all.
It's typical though as someone else said, the more brand loyal you become and the more you spend embracing these wonderful creations, the worse you are treated.
Jason
PS - On a positive note. iOS5 appears to have fixed my sticky home button issue, that apple wanted £129 to fix for me as I didn't have Applecare on my iPhone, so that's a positive.