hate to say it, but I think Thanos could destroy a lot of these guys with a few blasts (you know, the kind that knocked Galactus on his arse). whilst it'd take a long while for them to actually begin to strain Thanos.
obviously this battle looks lopsided, but as fluid/dynamic fight, I can see Thanos winning more often than not. he simply has to keep his distance from the Hulk, obliterate Superman and the GL (special K and some blasts should cover that), then he can take apart what's left.
Surfer can blast planets on a whim, Thanos is at the very least more powerful than that, imagine a series of unrelenting planet obliterating blasts - Hulk thrown into orbit as a result, GL and Thor hiding behind their shields whilst Superman is floored by a beam of intense kryptonite radiation.
btw, Flash would die first, because he would rush Thanos and get squished by one of Thanos' many shields/force fields.