Production - Logic Pro
I used to call this a sequencer - now it's called a DAW (Digital Audio Workstation). Of course the DAW's of today do a lot more than the sequencers of yesteryear.
I first messed around with a sequencer many years ago on an Atari ST. Back then you were simply recording MIDI from a keyboard and playing into an external synth module (I had the Roland MT-32).
I had fun but you couldn't really do anything that sounded anywhere near professional without spending fortunes on outboard equipment. So it got left to one side. In the meantime, other 'sequencers' appeared that could record audio. I tried a couple like Cakewalk's Sonar and even some dedicated Yamaha interface that fitted onto the front of the computer, but they were both plagued with driver problems - one PC would allow one thing thing to work but stopped another - it was hopeless so I gave up.
Finally I got a Mac - a stable and consistent piece of computer hardware at last with no driver hassles. I now had two choices - Avid ProTools or Logic Pro. I was pondering this when Apple plummeted their pricing on the professional software packages and there was no contest. Logic Pro studio, once well over a thousand pounds was now less than £200 - and it came with all kinds of goodies such as soft synths, sound libraries, etc.
So I set about my first album - creating it with Logic Pro 9. My second album was created with Logic Pro X - the latest version. Apple are constantly updating it with new features and library add-ons etc. and it has some great facilities. My only gripe is the sidechain bug - when you use the side-chain in a plugin, it causes the delay compensation in that channel to be bypassed so that channel plays first before the others! Looking through forums, this has been the case from early versions and I don't really know if other DAW's suffer from the same thing or not but it can be annoying. The solution is to output the channel to an Aux channel and put the side-chained plugin on that one instead (i.e. where there are no other plugins that cause latency). My main use for using a 'live' side-chain is to control the volume of one channel (using a compressor as a volume control) from the output of another. For example, an instrument kicks in and you want that instrument to be heard above others. Another way of achieving a similar effect, that I have been using a lot lately is to sample the frequency curve of the lead instrument(s) and subtract it from the instrument(s) that are to be put in the background. I use automation to do this and have used it a lot recently.
Another useful thing about Logic Pro X is the free Logic Remote app - available for both the iPhone and iPad. This is great for a home set-up. I use it mostly for recording myself while I'm on the other side of the room from my computer when I need maximum noise isolation. It saves me having to run from one end of the room to the other to stop and start recording and playback and is surprisingly powerful and easy to use and sets itself up automatically. It uses your wi-fi to control Logic Pro and the fact that it's free is an added bonus, of course.
There are now a large number of DAW's available - ProTools seems to be the number one choice if you are going to be using multiple platforms. Another that I have been hearing good things about is Reaper (this used to be free but is now a paid-for product). But whichever you use, be aware that they are complex pieces of software that you will be learning about for some time to come - although the best ones should appear to be simple when just doing the basics. Suffice it to say that I am really happy with Logic Pro and don't intend to change.