We've had processors that will support 64-bit operating systems for years now, but it seems that they are only just now catching on, or more specifically the 64-bit versions of Vista. According to a recent MS blog, twenty percent of Windows computers connecting to Windows Update were 64-bit, compared with just three percent back in March. Part of the reason for this is likely the fact that the mainstream retailers are now offering machines equipped with a 64-bit OS in larger numbers. If you factor in the reason that many performance users will go for a 64-bit operating system, that it supports more RAM (which is ever important), then it is logical that support is growing. With driver issues largely a thing of the past, there really isn't a good reason why you shouldn't go 64-bit for a new PC.