You can use
www.windizupdate.com (you cant use this through IE though)
Is similar to Windows Update but it was designed for people using the Mozilla \ Firefox browsers.
About 3 - 4 weeks behind Windows Update release wise.
Requires manual checking of updates though. ( I just browse to it each week or so)
I agree the Windows Update reminder can be a little annoying, but just another feature of the Windows environment been a little too user friendly, anyhow I suppose some people find it useful or it wouldn't be there.
Hope this helps
Mike Bedford
MCP | MCDST