Your first L-lens...

[marios_pittas]

Not quite the most obvious choice but for historic purposes at least: 24mm f/3.5 TS-E

-- Marios

 

[josias]

first is 17-40 for me too. fits my needs perfectly: travelling (lightest L lens and rugged build) & events (image quality, fast focus, decent aperture, great with flash). =D

 

[adamadam]

My first was 70-200 f/2.8 IS
2nd was 35 f/1.4