Yeah sounds like it, its normally a ggood sign when it starts clicking. I would download a HDD diagnostic tool from the HDD manufacturers site.
Its a toss up between the 2 of them. I mean 32 bit will probably have more drivers available than the 64 bit, and there isnt really any applications out for the 64 bit version yet to take advantage of the OS, but you might get slightly better performance from the 64bit OS (dont quote me on that tho). And all 32 bit programs should work on 64 bit