800 mhz memory and 64-bit?

I have few questions,

I ordered a T61 with 2 GB 667mhz memory and 32-bit Vista. I keep hearing that 32-bit is the way to go but will this change in the future? Am I going to want to go 64-bit in say, a year or two? If so, don't I have to get the 64-bit disks from MS or Lenovo now? Or do I have to buy it again later?

Which brings me to memory. When 800mhz memory is available will the current T61s be compatible with it? I was looking at Newegg and saw that I could get 4GB (667mhz) for only $200 which is only slightly more than Lenovo charges for 2GB. I just went with 2GB because the consensus on these boards seems to be that 2GB is plenty for most and 32-bit Vista won't 'see' all of 4GB anyway.

Long/Short: should I look forward to a fun little ~$200 upgrade in a year or so with 64-bit Vista and 4GB of 800mhz memory?

 

Microsoft hasn't really pushed 64-bit in their latest OS, and its likely, programs for the consumer market which support 64-bit, won't be released for years yet. The fact is that 64-bit may not offer all that much to the average user. I wouldn't worry about your notebook purchase with a 32-bit OS.

800 MHz RAM will not make a great deal of difference, when compared to 667 MHz RAM. This is only true, however, when you are running the 667 MHz RAM in dual channel, and you are also running both processor and memory depedant tasks. 2 GB is more than enough for the time being, and when more programs become RAM dependant, that is the time when an upgrade to 4 GB may be required.