My last two machines have had 64 bit processors. I have tried the 64 bit version of Ubuntu, and had issues getting things working well. The biggest and most obvious issue has been Adobe’s flash player.
Although there are ways to get it working, it would be ideal if it could be easily installed out-of-the-box.
Adobe has killed 64 bit flash for linux. Hopefully this is not a permanent discontinuing, as I would love to see this project succeed.