I've been following the forums for a while now, and there seems to be quite a few threads about race & professions combinations, about which ones are the most - or least - frequent, or about which combinations are the most fitting lorewise.
There are already some polls here on Guru but, as some people pointed out, they didn't get enough votes to be considered a very representative of the reality in game. Also, the latest polls were created right after the last Beta Weekend, and therefore they may be slightly biaised due to the fact that asura and sylvari had just been introduced.
There is, however, a pretty big database of race & professions choices (among other things) which has been around for quite a while: GW2 Census. I assume a lot of you know it already. The database currently has over 30000 characters, and you can create fancy charts with it. Obviously, it's still not perfectly representative of the choices players will make for their characters, but the database is large enough to give a pretty good idea of which combinations will be the most popular.
However, the GW Census charts are a bit limited, as they only allow you to compare 2 variables. I was curious to know which race & profession combinations were going the most and least popular, so I created a spreadsheet with numbers and percentages. You can see it here. I hope you find it useful. I wanted to also add gender choices in the tables, but unfortunately, due to the limitations of the Census' charts, it's not possible to figure it out.
Edit: GoodAndy from GW2 Census was kind enough to let me access some more detailed data, so gender is now included in the spreadsheet! Make sure to check his other project, GW Den.
TL;DR: Here be fancy spreadsheet and charts with colours showing popular race/prof combos.
Edit: Spreadsheet updated 14/08/2012.
Edit 2: Spreadsheet updated 18/08/2012 (now also includes gender choices).
Edited by JohnFireEye, 18 August 2012 - 05:54 PM.