Yeah, i read about how the extra bittage allows for usage of more ram, but seeing as i only have 2gb of ram, is there a notable difference? because i really want my adblock back..
I wouldn't worry too much about the 3rd party app - developers will most likely be releasing updates in the near future. In the mean time, you can just run Safari in 32-bit mode. If you don't like the performance difference (if you notice it), then you can decide whether you can do without the 3rd party app.
It seems to crash more often in 64-bit mode (when using the "Save Picture" command). Not that it crashes regularly, but it never did in 32-bit under OS X 10.5. And I'm not running any plug-ins, now, so you'd think it be more stable for that, if nothing else.