Blackberry?
I think these days it's phones, phones phones.
I find my BB Torch (ancient, now) to be pretty good for sound and so forth. It needs no special software (though BB's Desktop Sync Software claims to be able to sync music for you). I just plug mine in with a USB cable and copy mp3 files to the right subdirectory. It takes a micro SD card, so I guess I could put a 64GB one of those in if they exist.
In comparison to the other manufacturers RIM seem the least interested in locking you in:
- There is a BB music store, but it's really easy to just copy your own files on or use their desktop software to sync against your PC's music.
- BBM and music mix quite well - tracks bought through BBM can be officially shared with 50 BBM friends, and you can listen to their collection. If you've a lot of cooperative BBM friends it can be a good way of getting access to a lot of music with minimal outlay.
- There is a video store in North America, but I just copy the mp4 files on as I wish (I'm referring to a Playbook now).
- You do have to use their App store (mostly), but it's free for devs to put apps up on it so RIM AFAIK make no money from it directly.
- They don't try and push a specific email, calendar or contacts system, it'll work with equally well with anything that uses POP, IMAP, SMTP or Exchange Activesync. And their push notification system is clever, efficient and fast yet doesn't kill the battery.
- They do have BBM for the social side, but things like Facebook, Twitter, etc. get the benefit of their oh-so-clever-battery-and-data-saving-push-notification system too.
Personally I think that given their current situation they're just grateful if you buy a phone from them.
However, if the above pattern carries on into BB10 then a BB10 phone might be the answer. If BB10 is as good as the Playbook (on which it's based) then it's likely to be a pretty good solution. Their work / life separation technology (Blackberry Balance) in BB10 could be really good to, makes the whole BYOD far simpler to live with. I'm hanging on and will be examining it.
I wouldn't mind betting that Android is fairly liberal with the lock-in thing too, but I don't like it's lack of post-purchase updates and the anarchy of its app stores, malware, etc. We all know that Apple is totally for lock-in. I'm not yet convinced MS have got WinPhone8 right, but they certainly are trying to lock users in.