At the moment there are plenty of neg comments about the MN apps - you'd be better off with a browser, in my view. The one with the keyboard really does sound tempting as it overcomes many of the 'finger trouble' problems of either iPhone or Android users
One major plus, I'd say, (though iPhone users may want to share their knowledge,) concerns different browsers on Android... you could use Firefox, Chrome, Opera or Dolphin instead of the default browser. Not sure of your options other than Safari if using an iPhone... some of the others may be available.
Not sure if it is niceguy2, or someone else, but have seen someone who will happily recommend a Samsung over the iPhone now, despite having been an iPhone fanboy (and iMac user), and if you're already a GMail + Docs user, you'll have an account so can keep the phone in sync with your existing list of contacts etc.
As far as music is concerned, then do you want to simply stream audio from specific types of radio station, Shoutcast, etc ? If you like music and talk from radio stations, I'd go for a large data allowance - indeed, I'd even suggest switching network, given some are very stingy with data and/or charge a fortune... Sony Xperia T {older [6 months!] top of the range Android} on Three is in the 20-30 pounds a month range, which might be similar to your existing contract, but obviously without knowing what you pay, your needs {minutes, texts, data} it's not easy to guess whether that's higher or lower than you pay, and anyway, network coverage is another factor. Anyway that Sony has one of the cameras that would compete with the iPhone and top end Samsung phones, and you'd get 50 GB of storage online for MP3s, films, documents, etc, for free.
WinAmp (free) is now on Android which will play your MP3s (simply plug in most phones and the internal storage {+ microSD card if you want, pretty much any Android can have extra storage plugged in}) will be visible on a PC so you can copy to/from the phone with the file manager... no need for iTunes to 'sync' with the phone.
TuneIn Radio has all the BBC and many worldwide stations, so I listen a lot to some from SoMa (South of Market Street, San Francisco), plus various news/talk/music from across USA/Canada, and more locally, World Radio Network from London (with broadcasts in English from many parts of Europe, and further afield).
Just reminded me it's Saturday and "Wait, Wait, Don't Tell Me" a US news quiz will be on, along with a number of other variety shows, such as West Coast Live from San Francisco, via a station called KALW if memory serves... It's on later, at 18:00 UK time, 10:00 West Coast :)
(I used to listen to some of these via satellite in the past, and Europe, Australia, via short-wave, but now it's so easy with the internet!)