I installed 32-bit linux because back in the day 64-bit linux missed out on some cool stuff like java and flash. Some of those things have been resolved (maybe all, I'm not as up-to-date as I was) and currently I'm having performance issues with the 32-bit versions of the ATI binary driver. The machine I'm on is 64-bit wide so I could switch to 64-bit, but I'd like to do so only if there is an advantage to it.
tl/dr;
Are 64-bit ATI binary drivers better/faster than their 32-bit counterparts?
UPDATE:
With the shift to 64-bit a lot of things change at the instruction and hardware levels. I would expect 64-bit drivers to be able to process more data in a shorter amount of time. I don't know if the types of operations that GPUs benefit in this way or not. My feeling is yes, but by how much I don't know. So I'd like to know if anyone has spec'd a GPU (specifically an ATI one, since that's what I have) using 32-bit and 64-bit drivers and seen a vast increase in speed on the 64-bit one.
AFIK, 64 bit Ubuntu has been as easy to use as 32 bit ubuntu for several years now. If you have the hardware you should start with 64 bit Ubuntu and if you have a specific problem with a specific 64 bit package fall back to 32 bit.
Such a problem would be unexpected and it has been a long time since I have seen 64 bit fail. If I said never, someone would post a counter example.
tl/dr ;
I see no reason not to use 64 bit Ubuntu / 64 bit ATI driver and in theory it should be faster then 32 bit, but I do not have the benchmarks to prove it.