Battle of Ipsus

The result of the battle was victory for seleucus and lysimachus and defeat and death for antigonus. 

What are peoples opinions on this battle?  What do you think would have happened if Antigonus would have won?  Perhaps keeping the empire of alexander intact?

You bring up some interesting points, I wonder though if the antigonids win at ipsus they can concentrate on ptolemy then the far east.  I would think their chances would increase a good amount if ipsus is a victory, seleucus, lysimachus and cassander would be all but neutralized for a while with just ptolemy left excluding the far east territories.  I disagree about them inevitably falling to the romans.  There have been some lively discussions about alexander versus hannibal and the romans on other threads and my point has been that it may seem like it was inevitable that the romans would beat the hellenistic empires however, the successors were impoverished and were never able to meet the romans with strong cavalry or their best infantry.  If the entire or most of alexanders empire is united I would think it could field strong armies with a strong cavalry arm.  Being able to properly execute the good old hammer and anvil tactics of alexander and phillip with perhaps some newer modifications.  I agree that with the death of antigonus, seleucus was the strongest of the diadochi, only ptolemy could compete.  Yes it was rather like a see-saw in regards to the ptolemaics and seleucids, often times it was the seleucids soundly beating the ptolemaics. (they almost conquered egypt several times if I am not mistaken)  I would say the seleucids were experiencing a revival under antiochus he had secured the eastern borders with parthia, bactria and india and was overall successful against the ptolemaics; until he was defeated by the romans.  After this everyone rebelled and he would have had to repeat his previous achievements all over again.  I can completely understand the partiality to the seleucids, I am rather partial to them myself.  The diadochi allied to the carthaginians, now that is interesting.  Hannibal had tried to get Phillip V of macedon involved in his war with rome but nothing really concrete ever came of it except rome going after phillip once hannibal was defeated.  Talk about a what if.