Nick,
Sorry I always seem to be the one to throw my opinion at you, but having owned Cakewalk, Cubase, and Logic, I couldn't see ever switching off Logic. (I haven't used Acid)
On the plus side, Logic has a great workflow for me. Once you get the hang of its controls and quick-keys, you can work very quickly without spending a lot of time on software hassle. It just works like it should. The included plugin suite, EXS instrument set, and sample library are, IMHO, top of their class as far as included software goes. It also has some really nice templates built in for various control surfaces, so if you're using a Tascam, M-Audio, Digidesign, Mackie, Roland, or Yamaha controller, you just plug it in and it "works."
Logic does have a bit of a learning curve for new users. It took me a few weeks of fiddling with it, reading the (gigantic) manual, and leaning on Baker here on the forum to really get up to speed. I still know there's a lot more under the surface that I haven't explored.
P.S. FWIW, my Logic rig runs on a Mac Mini, 1.83GHtz, 2GB Ram, 120 GB Drive, 160GB Iomega eGo backup drive, Apogee Duet & Tascam FW-1082 interfaces.