All of them are optional.
Have you seen Table 1 in Mim0's updates List?
When you have every IE6 Updates and hide IE8, there you'll see IE7 (and after install IE7, IE7 updates) and the same happens if you have WM8 updates, you'll see WMP11 and if you hide it, you'll see WMP10
There is RDC6 in XP and i think if IE8 is high priority, IE6 updates shouldn't exist in updates list (i'm not saying in WU).
RDC7 replaces RDC6 as those HBR replaces other updates (call it 'time zone' as example).
AD or Active directory updates has been removed because in no way exists any AD version in XP.
When i install XP updated, windows updates shows Windows Live Essentials as optional update but it is not in the updates lists (and i don't care because i don't use it). Do you wonder why?
You will find out that Microsoft did mess up something in the update lists.
Okay, here is some basic info:
1. Microsoft still maintain both IE6, IE7, and IE8, so you can see they offer updates for all three versions.
2. IE8 is high-priority as X said. (But IE8 still sucks. You better use a good browser like Firefox or Chrome.)
3. IE6 and IE7 are both obsolete. Really. MS don't want people to use them anymore. Kogan even imposes tax on IE7 users. (You can Google these to find out: "IE6 countdown", "IE7 tax")
4. WMP11 and RDC7 are optional.
5. I've never seen Active Directory or Windows Live Essentials in the Windows Update list. I never use them either.
6. You should forget anything WMP8. Windows XP SP3 is shipped with WMP9.
Edited by Explorer09, 02 July 2013 - 08:34 AM.