A list of tasks recommended for maximum experience:

4 - Propaganda
5-9 - Terrorist Financier
10-11 - Dirty Bomb
12-14 - Forge Passport
15-17 - Propaganda
18-19 - Minister
20-21 - Shortwave
22 - Train Revs
23 - Train Revs/Provoke
24 - Train Revs
25-30 - Unhinged
31-32 - Stop Nukes
33 - Baccarat
34-35 - Intercept
36-40 - No tasking, start assassinating