OpenELEC, XBMCbuntu or Ubuntu?

First off, sorry if this topic has been discussed ad nausea, but I didn't see exactly what I wanted and I never know where its more frowned upon to bump an old thread or start a new one, so anywhere's here I am.

I am in the process of my first HTPC build (exciting!) and I'm trying to decide which OS I want to install. As the title suggests, I'm trying to decide between OpenELEC, XBMCbuntu or Ubuntu. My system has a i3-3225, SSD, 8gb Ram, a BR drive/writer and ASRock H77M mobo all inside a Wesena e5 v3 (I'll be using my Onboard graphics as the i3 has Intel HD 4000).

I serve files through NFS on a Synology NAS and a vast majority of the time I'll be using the HTPC to watch videos in XBMC from the NAS and i'd like to watch DVD's and BD's as easily as possible. For these needs, I would think OpenELEC is my best bet, but also, and much less frequently, I'd like to use a few other programs to consume media, specifically:

• Hulu
• Netflix
• ESPN3
• Spotify
• Youtube
  

and possibly other internet content providers. I wish wish wish I could get the Music portion of XBMC to work for me but it just doesn't seem to be able to handle my rather large (>500gb) music collection, so I'd really like to be able to use another program to serve music, but more than likely the HTPC would just act as a Airplay client.

I guess I'm asking if there are ways to easily accomplish the above with an OpenELEC installation and, more generally, if the clean, low-imprint installation of OpenELEC or XBMCbuntu is worth the inconvenience of not having an all-out OS?