^ i second that
you have 4 gb but you are only using like 3.75 gigs
(if you have less than 4 gb upgrading to 64 bit might have some benefits but i noticed on my main desktop when it had 2 gigs of ram (i upgraded to 64 bit then got more ram) when it was 32 bit it used less ram (clean install) than 64 bit (again clean install) - both windows 7 ultimate)
tl;dr if you have 4 gigs of ram 64 bit systems can be of more use if not it kinda depends you might (thats MIGHT as in you might not) get more out of a 32 bit system - i havent tested my theory if someone can/already has then results pls?
my tl;dr wasnt all that short now was it...
i give up...