AMD notebook already using 64bit. Intel expected to release 64bit second half of next year. Windows Vista is expected to release by the end of next year. Vista support 64bit.
if u can wait a year. of course it's a good idea to wait for 64bit. however, i think 64bit advantage is not oberious on notebook. since so far.. the biggest advantage of 64 bit is memory addressing. notebook computer rarely have memory bigger than 4GB.
Desktop computer is 64bit ready for almost a year from now... i rarely heard people say their computer runs so much better than 32bit.
however, if u can wait a little. Dual-core centrino (Napa) is around the corner. which i think offer more advantage than 64bit.