Many composers have used Logic, Cubase, Finale, Sibelius, Reason, or some such to create music, then exported the project into Pro Tools only for audio recording and editing. With the new Pro Tools 8 (£190 and up, depending on related hardware), users can realistically use Pro Tools as a one-stop composing/recording shop.
The addition of a nicely-realized piano roll MIDI step-editor and better-than-good score editor makes composing a far, far more pleasant experience. Not only that, the new version's look has improved substantially. Unfortunately, the makeover extends only as far as the contents of the windows. In most cases, menus and dialogs in the PC version still have an antiquated Windows 98/XP look. The program still employs the Windows Multiple Document Interface, so you have to often have to navigate through stacks of child windows (though it's much politer about this than rival Cubase).
Before you shift into "I wanna use what the pros use" mode and rush out to buy Pro Tools, there are a few things you need to know. First off, it's not just software; it's inextricably linked to Digidesign HD hardware on the high end and the Digidesign Mbox and M-Audio hardware (if it sports the M-Powered label) on the low end. It won't recognize or use other audio interfaces. Unless you're dead set on using existing, unsupported hardware, this shouldn't be a problem; the linked high-end gear sounds spectacular, and the low-end ain't half bad.
The other thing to know is that Pro Tools doesn't support Steinberg's VST, the de facto plug-in standard used by the rest of the industry. This isn't too limiting; Pro Tools has its own RTAS standard for plug-ins, which is supported by most of the larger vendors. In other words, if you buy a popular plug-in effect or virtual instrument, the odds are it will include functionally identical RTAS versions. Less popular plug-ins and even some popular ones may not. Caveats aside, I enjoyed this version of Pro Tools far more than any of its previous ones. There's something about Pro Tools' clean, uncluttered interface that helps you get down to business. It has none of the tool and icon clutter that plague Cubase and Sonar. The program is also very solid; I've never seen it crash on my PC, though the install has crashed occasionally.
If you're working on a project that you eventually want to take into the studio for recording vocals or instruments that require expensive, high-quality mics and/or isolation booths, then Pro Tools is a no-brainer (M-Powered as long as you're okay with its 44.1kHz limitation). Even if you create using another program, it might be worth transferring the audio over to save the expense of a pro engineer's time converting it. It's especially appealing since you can buy a Digidesign Mbox audio interface with Pro Tools LE for about £250. That, my friends - given the new creative features - is a heck of a deal.
As a creative DAW, this much-improved version Pro Tools faces stiff competition from the programs I named up front as well as others such as FL Studio and Ableton Live - all of which support ASIO, VST and nearly any audio interface on the market. But as of version 8, Pro Tools is definitely a contender on the low-end. It of course remains a studio staple on the high-end. Alas, to take a test drive you'll need to visit your local music store, though you can learn a lot from online demos and tutorials.