If you try to update eclipse or any eclipse based product (f.e. RAD) and it takes 2 hours to display first update window... you probably are in a big company, behind the proxy, and with local DNS servers that do not know anything about internet.
Please call your network administrator and tell him to configure DNS to answer server failed, and not to pretend to not exist... cause Update Manager contacts eclipse update sites *before* displaying the first update window... and it does it a lot of times. Default timeout for DNS query is about half a minute...
And now good news: new update manager will be shipped with Eclipse 3.4 (next summer).