**Sonofa*****
I just spent 15 minutes typing a really long reply, and when I hit submit, I had been auto-logged out, and lost all of it.
I'm not doing that again, so here is the short(-ish) version instead. Please note that since you haven't settled on a trading provider, and haven't stated what
type of trader you are, then there's only so far that we can go with specific advice.
I've been trading for a living for several years. Started out with Mac Pro, now have dedicated trading PC. Here are my specs;
CPU: Q9550 2.83GHz quad-core
Mem: 2GB
Graphics: 8600GT dual-DVI
Monitors: Dual 1920x1200
Hard Drive: doesn't matter, anything will do.
Trading on a Mac is just not your best option. Trading in a Virtual Machine is asking for trouble, and limiting yourself to platforms that run natively on the Mac is unnecessarily restrictive.
They key to my setup is that I use the trading PC only for trading. I don't even run a browser on it. No anti-virus, no email, no IM, no web browser. Just the programs I need to trade. That reduces the chances of another program competing for system resources, and also minimizes the risk of getting a virus. A lean and mean dedicated trading machine.
I use my Mac Pro for everything else, including market research, etc. Keep it all off your trading PC.
With this setup, my trading PC can easily handle busy market times - CPU rarely get's above 30%, and my memory usage is a constant 1GB. I run Tradestation, Ninjatrader, and sometimes Interactive Broker's TWS, along with two data feeds. Network bandwidth hits 1-2Mbps during market open and close, but usually only for a minute or so. More importantly, my PC remains
responsive at all times.
So bottom line advice is this - get a quad core PC with 4GB memory and a dual-DVI video card (get a cheap one, you don't need much power, we're not playing video games). Put a clean install of Windows 7 on it, and only install the programs you need for trading. Get two of the biggest (resolution-wise, not size-wise) monitors you can afford. Screen real estate is everything.
Then get a third monitor and hook it up to one of your mac laptops (or get a mac mini), and use that for all of your non-trading stuff, including market research, excel spreadsheets, etc.
If you are comfortable building your own PC, you can get all of the parts for around $600. Use the rest of the $$ you were going to blow on a high end box on more monitors instead. Super fast CPUs/memory/hard drives are just not going to make a difference here.
Let me know if you need more specific recommendations.