I was thinking of the values you would ultimately store in the database and what you might use them for eventually. If you want to use these times in a SQL expression in the WHERE clause through direct SQL or through DAL expressions and search across multiple users for something created between time X and Y then they should all be resolved and then stored to the same time zone not different ones. In that case you would want to work in UTC on the server and then convert using Javascript in the user's browser since the user's workstation should have the proper setting for the time zone they are in which will trickle down through the browser and the Javascript code to convert between UTC and local time for each particular user.
However, since there is no real background for what you want to do with the time values from the application perspective it is difficult to advise you without some speculation. :-) Massimo's comment is spot on. The default in the server is to generate the time as the local time of the server when the request comes in which again would be consistent if all your servers are in the same timezone. To get UTC just assign request.now = datetime.utcnow() and use the value consistently. If you never intend to use the times for comparison across multiple users then you can store in the user's local time but I think you will also need to store the user's timezone as well to be able to render it back out to the user later for display.
