The game -- actually playing the game -- runs great. No issues of lag whatsoever....But when I do anything involving the main menu... (the load/save game one) but NOT the inventory/map/etc menu ... the cursor suffers ridiculous lag to the point where clicking things takes a huge amount of random luck before it works.

Like I said, everything else running just fine. Its that one main menu, mostly the save/load sections, that go insanely slow and lag. This happens whenever the game is loaded. Doesnt matter if I'm trying to save from within the game or trying to open a saved game after first launching skyrim. Due to the relatively harmless nature of this bug, and its zero effect on gameplay, its not too much of a problem.

But it is really weird nonetheless.

I think it's reading all your savegames, at 10-12MB each it can create quite a pause.
Yes I feel it too, but not too bad and it's pretty brief.
Big fast defragged harddisks or of course SSDs will help.
The effect is minimized on PCs with the most powerful overall platforms and storage systems.

And i thought it was lagin in and out as it loaded differant PICs for the different saves....Point to one save ..smooth...move mouse down list and PIC changes if you click on a different save....this is when i have noticed the pause/hitch.

Was much worse before I moved/deleted a bunch of saves....trimmed down to 12 Saves and is smooth...

Make sure 'Vibration' and '360 Controller' are unticked in your options.