11-14-2012 04:37 PM - edited 11-14-2012 04:48 PM
35L followed shortly by the 135L.
Since my first camera (along with many others after it) weren't Canons I'll just give the time between purchasing my first Canon body (a used 5D2) to when I purchased the 35L which was 6 months (the 135L came 2 months later).
I guess the sacrafice would be the money it cost to purchase the lens, but while I did want it I also needed it to do my job.
11-14-2012 07:11 PM
My own first L is the 70-200 2.8 IS II after six months on 60D. Three months saving up for this gem of a lens!
My 200mm Rolleinar MC 3.5 gets less used on the 60D and more on my 600D now.
For a long time at work had been using the 16-35mm 2.8 LII and 24-105 with 5D mk2.