64-bit is only an issue if you install a lot of older programs/games (like me), so if that is the case for you, I'd also suggest going with 32-bit. (Do note though, with 32-bit any memory over ~3GB would be unusable.)
Ultimate vs Premium...I have both (laptop/desktop) and can tell you for a fact there is zero difference for general use...beyond the "extras" Ultimate gets (click here to see what I mean - old and useless
), so if there is a price gap, I'd definitely get the cheaper one.
When I bought mine, there was a $5 difference from Premium to Ultimate, which is why I figured 'what the heck'.
What's that setup runnin' $-wise?