I'd suggest to check out a playlist that I made of one of the major events at SXSW (happened 2 weeks ago). It doesn't contain only indie music per say but you'll find that the majority of the music videos are from indie bands. I would also like to say that it's mostly only one music video per band. The Hype Machine Hype Hotel showcase had a lineup of over 50 bands so you'll excuse me...
Some bands already mentionned that are in the playlist:
^ I don't recommend buying that White Lies 2nd album. That song is pretty good but the album is poor and their first album is better (but not strong). They've produced some very good singles so far but lack consistency.
I recommended The Jezabels in the earlier post. This band has more albums and they're not as good but their 1st album is worth buying, other two are okay. The voice of the lead singer is great (and she looks a bit like Zooey Deschanel).
Would also recommend Sportfreunde Stiller, very good German band. They make some pretty catchy radio hit type songs (not that I can understand them).