Microsoft has stated after the vista fiasco they will release windows 7 in 3 years time come hell or high water.
Vista 32 and 64 has same aggro as XP home and pro, where pro was more secure than home.
Vista 32 is cut down version of 64 and as more 32 vista out their software houses will release drivers for 32, and Vista 64 as smaller base will have less support to 32 but!!!!!!!!!,  Vista 64 wipes the floor with Vista 32.
Vista 64 has higher security than 32 and unlike 32 the 64 version has between 1 to 256 boot sectors to start windows from, it means every time you turn comp on windows will randomise between those numbers where to boot windows from.
So the advantage unlike Vista 32 is anyone trying download Trojan to boot sector are screwed as if they install to sector 1 a Trojan, windows has another 254 boot sectors to choose from.
Do love the way Microsoft treat certain windows users as peasants/peons in the security for higher windows versions.