I PREFER to start on measure 2 because it's easier to follow the math (I omitted the 's' from the end of 'maths' for all you Americans out there ;P). Simple as that really. I'll sometimes change the time signature if there is an odd number of measures (or a half measure etc) in a section in a song just to keep everything sitting on a nice even number. Makes arranging easier.

Changing time signatures is a great way of making things line up nicely. It's also very clearly distinguishable on the grid lines.

I'll jump in this discussion as someone who never really understood the negative bars request, but has now completely come around and it is a worth while request. After we're finished a song or track, there may be some other things we need/want to do. For some film purposes, we've added vocal tracks before the track as cues or lead-ins such as in how we used to use bars and tone for videos. The other is when we use our songs in a live on-stage purpose... We have some songs with strings or electronic pieces that we want to be triggered live for the band to build a bigger show or MIDI to control lights. With a completed song, you have to produce the song and export it for recording beginning at the start. TO add vocal cues or lead-ins, you now have to shift the 'song' a certain amount of measures to the right. You either end up with 2 separate files or you try to keep shifting the song back and forth for export versus for live use. While it's not necessary and is a feature that a minority of people will use, I do now see WHY it is being requested. It would help in certain situations to be able to do it.

I think it has been said here, but you can use the Meter/Key view to make the first measure 1 or 2 beats and then start your normal time signature at the next bar.

That would do exactly what you need except that it would call your first bar 2 instead of 1. 

I always have at least two blank bars anyway to allow time for set-up of the various synths, lock-up if I am syncing, etc.  This is not as important as it used to be beause computers are faster, but I still think you will find that starting MIDI instruments right at the top of the first beat of your project will result in some jerky lurching starts.

I personally would love this, best sonar feature request ever IMO.

I, being of the age that I am :) .... have always made it a habit to have 3 or 4 bars (or even more depending on the tempo of the song) before a song starts. This goes back to the days when I was syncing SMPTE to a striped track on a multitrack TAPE machine. With computers back then, it might take 4 seconds to lock up to the time code. Although PCs are much faster today, they can still take a second or so to lock up to an external TC source. Most people no longer need to do this...but old habits are hard to break ;) .

This thread is self repetitive, to say the least, so I repeat myself as well. Some say they want  "sub-zeros" some say two empty bars will do.

The "sub zero" alternative, though, is the one that allows you to count measures and structures "real time" without extra math. If you make a song with 4 measure intro, 12 measure verses etc. and you have those structures in your head, it's annoying to go " ok, I change that thing in measure 11, which means it's actually measure 9....".

In times gone by, I used to start my projects with four, single beat bars, and start at measure 5. I found, at the time, it helped with my maths...

Another Option: Start your music at Bar 2, but put post-it notes on the screen with the desired bar numbers.