I predicted about a year and a half ago that M.I.A. was eventually going to be a massive international superstar and not only do I continue to stand by that, but I think she's well on her way (when I made my daring, handsome prediction before, "Paper Planes" hadn't blown up yet). At the very least, she'll be at Bjork's or Gwen Stefani's level, but I think she'll eclipse both of them and approach Madonna levels.
She's got a unique mashed-up ethnic vibe and look that the girlies will emulate and the men will get boners over. She's shown a willingness to experiment madly with her sound, which is already an interesting mix of world, hip-hop, indie and pop. And because of her influences and ethnicity, she could play hugely in a lot of developing markets.
And, hell, her music is really good.