The only problem i can see is that your DVd/BD player will be region 1 only, some BD disks are multiregion there's a few sites telling you which ones. Games are not region encoded so any game from any region should play, but there are a few cases (bout 3 or 4!) were games multiplayer part is region locked. The other issue is that it will be highly doubtful Sony UK would honor the warranty if the US version went wrong.
Need to remember you can't play UK PS2 games on a US PS3.
It is down to the NTSC/PAL thing. Is Australia PAL? if so then you wont get the backwards compatibility anyway.