So, the Second Life Universal Binary Alpha runs quite well on the intel iMac. In fact, I can run it and World of Warcraft at the same time. Performance on both suffers (WoW drops to 15fps in Org), of course, but surprisingly both are still playable.
Of course, I can't really play both at the same time unless it's just socializing, or tradeskills in World of Warcraft. My machine might be able to handle it, but my brain can't quite.
Anyhow, well done Linden Labs.
PS: Look, I found an Irish (looking) pub in SL.