I trade both from a local machine and a server co-located at the CME.
My local machine is a PC from FelinePC.
I use this PC for software development, testing, and for my discretionary trading (my algorithmically derived trades are managed via a co-located server at the CME).
I have been actively trading for 18 years and have been through a tremendous amount of computers, and hardware vendors, and have never experienced the service, value, and knowledge that Mike from FelinePC provides.
If you are looking for a trading computer, I highly recommend FelinePC.
Chief Algorithmic Architect