I tried them all when I migrated to the Mac a few months ago, and my favourite (not even by a bit, but by leaps and bounds) is
iBank. I didn't do a lot with multiple currencies, but when I had an account with a GBP balance, it handled it (along with my USD accounts) with no problem. Most importantly, the developer is receptive to user feedback and responsive to inquiries. I got an e-mail in response to a crash report I'd submitted while they were at MacWorld, which I found pretty impressive. Anyway, this thread's quite old now, but if anyone is still looking for a proper personal finance app, iBank's got potential and is worth a look.
(I've no vested interest in its success, I'm just a happy user.)