For many years, the two big players in the software sequencing market - at least as far as Europe goes - were the originals: Emagic's Logic and Steinberg's Cubase. Although Emagic is now owned by Apple, they are both still going strong, and have now been joined by two offerings from the USA: Twelve Tone's 'Cakewalk' sequencing software was the first successful Windows based sequencer (always popular in the States), which has since evolved along with their name into Cakewalk's 'Sonar', and Digidesign's 'Pro Tools' which comes from the audio side of recording and has only fairly recently added professional level MIDI sequencing. Although not very popular outside the America, MOTU's Digital Performer is also a very credible program.
At a broad level, these five software recording studios offer essentially the same facilities. They are very similar in layout, features and workflow, and choosing which is best for you will often come down to whose style of presentation you prefer, or which one your best mate uses so they can help you if you get stuck! The upside is that whichever one you choose, you can rest assured that it will do a good job of all the processes we have described in this article. There are a few caveats however - Logic now only runs on Apple Mac computers, Sonar only runs on Windows, and Pro Tools only works with Digidesign's own audio interfaces, or those of M-Audio in the case of the 'junior' Pro Tools 'M-Powered' version.
In recent years there's been a healthy rebellion against the perceived monopoly of the big names, and some strong alternatives have emerged. Propellerhead's Reason is a great way to get into software sequencing, offering an analogue based method of working, although it also contains the usual MIDI editing features of piano-roll and automation. Ableton's 'Live' on the other hand approaches sequencing from the angle of looping and performance. Originally based purely on audio loops, it allows you to stack them up for triggering in groups, switching between verses and choruses with a single click, making it a very intuitive jamming and improvisational tool. As its potential was realised, MIDI was bolted on, and it now includes the same sort of audio/MIDI recording as the traditional programs, while maintaining a heavy bent towards performance. Lastly, another program, 'Tracktion', now owned by Mackie, was reportedly originally written by a lone programmer, fed up and frustrated with the way that Cubase et al worked, who set out to create a working recording studio that was easier to use and a good deal cheaper - if you don't consider yourself likely to become a 'power user', you may well find that this will cover all your needs.