I use IntelliJ - it makes Java bearable and is the king of the J-IDEs.
I have downloaded Eclipse at least a half dozen times and each time I've found it to be an incomprehensible collection of random controls. IOW, I just don't get where it is coming from and haven't found any decent documentation anywhere to help me understand its mindset. My conclusion - its crap designed by the same people who do UI for MS.
Have you checked out all of the plugins for IntelliJ? There may be one that adds nicer starteam integration.
Frankly, I'd question the utility of starteam if it required the loss of IntelliJ - I'd consider it to be a net loss.