I have Lonely Planet Bangkok guide book, True ThaiGuide, EnThai dictionary, BKK Transit as mentioned above, and TomTom Thailand navigation program.
I'm not sure if it's worth to get one-2-call SIM over true SIM.
And true's unlimited GRPS/EDGE plan is only THB599 per month, and 799 with wifi.
Last time I was in Bangkok, True wifi was everywhere, so it might be worth it to check out.