Have a look at ProTA, http://www.beesoft.net/index.html
I will most likely be using this once i get my new mac in the next couple of months. Has no intraday updates, only EOD but looks to be the best out there for mac users.
The other alternative is if you have one of the new intel macs, you could use bootcamp and run windows xp/vista to run a windows based charting package
