Only a small percentage of updates actually show up on Windowsupdate. Microsoft only ever (essentially) releases software updates and secutiry fixes, not hotfixes via Windowsupdate or Microsoft download. Hotfixes are available via request. There are literally hundreds of hotfixes between service pack releases, and already well over 100 hotfixes since Vista SP2 (as an example). They aren't bad to install, just they only affect a small number of people. These updates are all included in service packs. A couple of these updates like 123456 are most likely test updates. They do no harm, but no benefit either. The rest are proper updates or hotfixes. Some are even officially available via hotifx request now. Some may be older versions of the same updates available via request.
you do not need to download ANY of the updates posted on this forum or anywhere else. 98% of the updates posted were for RC candidates of Win7, and most of the newer ones people were posting were beta updates for a future final version of the update. Also, not all updates apply to all computers. So you would be installing crap you didn't even need. Stick to what appears only in windows update, and not this crap everyone is posting, unless you want to mess up your installation. MS is posting updates on WU now.
The recent updates are all for the RTM Windows, not the RC. They will all eventually be available via either WU or via hotfix request. Most updates for Windows are actually hotfixes, only a small amount of those updates will show on Windows Update. Everyone will get all the updates eventually once the Service Pack is released, upon which time the cycle starts over again. There is less need to install the leaked updates now than before, but between the date when RTM became available (late July) and the date it was officially released (a few days ago) it actually made sense to install the updates. IF! you were concerned during this period of installing the leaked updates, then you probably shouldn't have bothered with Windows 7 at all until it was offiicially released and official updates and security updates were released.
If they are hotfixes, they can be found on the microsoft website using the kb number. If they cannot be found, they are beta and not ready to be published. How many of them can you find? I know about 1 hotfix only. The Hofix Share and other websites classify those update as beta, too.