At this point, if it were me I'd wait until the new laptops with
Windows 7 come out (Oct/Nov). You might want to check to see if there is a free upgrade to Win7 if you purchase a laptop closer to Oct when Win7 ships.
Win7 smooths out most of Vista's rough edges and feels noticeably faster (to me anyway) and is much less computer resource intensive. Both Vista and Win7 have a compatibility setting the user can apply to older programs that do version checking, to trick them into thinking they are running on a down-level OS (Vista, Win2000, Win9x, etc).
64-bit
Windows editions (XP, Vista and Win7) have an emulation layer that allows it to run 32bit software. Most of my software is pretty mainstream, but I haven't hit anything yet that couldn't be run natively or via the compatibility setting changes. The nice thing about 64-bit software and operating systems is that you can use all the
RAM on the box. 32-bit operating systems are limited to about 3.5GB of
RAM (possibly wasting 1/2 GB
RAM which could be put to good use - you paid for it, so you may as well use it).
FTM2010 runs just fine on Win7 x64. Others have run FTM16 under Vista x64 using the compatibility settings and report it works well.
Hope this helps.