Updates to Avoid
Yeah, this is tricky... As a general rule, as folks have been saying, it's best to let it update everything, as this minimizes the number of security holes in there...
However, this discounts two things: how paranoid you want to be about MS invading your privacy, and how much you're prepared to put up with having Windows 10 forced on you. (Oh, and also thirdly, wanting to get away with using a pirated version of Windows, or at least one that won't activate as genuine, which isn't always the same thing)...
So... If you don't want Windows 10, you're best off avoiding these:
KB2952664 KB2976978 KB2977759 KB2990214 KB3021917 KB3035583
as they're all Windows 10 preparation updates.
If you're worried about being spied upon, I'd give these a miss:
KB3022345 KB3068708 KB3075249 KB3080149
as they bring Windows 7 "telemetry" stuff into line with Windows 10. (This is info that gets phoned-home from your copy of Windows back to Microsoft. In all probability it is just info to help them identify reasons for software crashes etc, but given wording like:
"Finally, we will access, disclose and preserve personal data, including your content (such as the content of your emails, other private communications or files in private folders), when we have a good faith belief that doing so is necessary."
in Windows 10's EULA, I won't blame anyone who feels paranoid.)
And lastly, if you're having trouble getting Windows to validate as being genuine (whether because you're running a pirated copy and your crack tools aren't working properly all of a sudden, or because your actually valid copy of Windows isn't validating) then avoid this one:
KB971033