Seeing that it is apparently a regular thing at the moment and that as far as I have seen, appears to be disproportinately 64bit users, I have noticed a probable cause that's not mod related...

Can those that are experiencing random CTDs on 64bit systems, with 1.8 patch, please check that when they first run skyrim, on the task manager (ie ctrl alt del) whether it states TesV*32 in the list?
Mine does and seems to explain why my random crahses are all when the memory usage is around 2GB.

I have also checked my exe in a hex editor (as it explains http://superuser.com/questions/103071/quick-way-to-tell-if-an-installed-application-is-64-bit-or-32-bit, about 1/2 way down) and it apparently shows the game to be running in 32bit mode??? Yes I have verified my game cache through Steam - earlier today infact, it's current.

Query for those in the know a bit more than I (inc & esp Bethesda), could the 1.8 patch have included an exe without the LAA flag? Does all this even matter, has anyone else noticed this?

The game is only a 32-bit executabe with LAA enabled, so it uses at maximum 4 GB of RAM. The base game has absolutely no issues as a 32-bit executable.

64-bit support has been discussed to death, so simply search and you'll find them. In my opinion, we really don't need to bring up the topic again but that's me. /shrug

In other words, this is not your problem. You've got a different problem.

That said, let's start from the top:

1) Post a full dxdiag in a spoiler tag
2) Try a completely clean install, with brand spanking new INIs produced by the game and not edited by you. The latter is done by deleting any and all INIs for Skyrim from your system and then verifying the files.
3) Try a new game
4) Ensure you have not installed to the Program Files directory on the system's root drive, as this is a protected directory and can cause any number of weird things to happen
5) Remove any and all mods, third-party add-ons, script extenders, etc. Remove, do not simply disable them.

That list is not in any particular order except for the order in which I thought of them.