How much RAM does your laptop have? If it's over 3Gb, the 32bit kernel won't make use of the extra and Ubuntu does not offer a PAE kernel option for 32bit systems (you could still compile it yourself).

There have been several quirks with 64bit OS apps such as Flash player or Java. Adobe has released a beta version of Flash 10 for 64bit linux and it works quite well.

If you don't have the RAM requirement I would stick with 32bit just for avoiding any potential 64bit complexities.


-twig