Navigation For *walking* On Mobile Phone -- And Which Sim Card ?

Hi, I would like to have map navigation on my mobile for *walking* in Bangkok and probably for general use in Central Thailand. The phones I could use are a Nokia Symbian Belle or a new Android 4.1 (not iOS and not WP8).

Which map service is helpful to walk around without getting lost? Using Google Maps (online or offline/downloaded) sounds very interesting, but in the past I also liked Nokia's own maps. I would prefer to get directions by arrows on-screen instead by voice, but maybe that's not an option.

So which navigation for mobile phones do you recommend? It could also be a non-free map and I would need navigation later also for Bangladesh and India.

On the same matter, which SIM card do you recommend for a few tourist weeks in Thailand, never in very remote areas? I do want to use internet on my mobile regularly, but not excessivly (will have laptop and wifi also); but as a tourist I only need a prepaid card. No need to find the very cheapest SIM, if other SIM cards are more comfortable or stable. In the past I used the DTAC booth at the airport to get a SIM card and credit right there; it was ok and seemed easier to use for a foreigner than some offers, but I never used a SIM card in Thailand for data so far. I don't know if the providers in Thailand offer their own online maps and if yes, if helpful and with English instructions.

While at it you could tell me if you recommend any app especially for Thailand, for instance dictionary, restaurant finder or some such. I'd even pay money for a good app.

Thanks for all your suggestions!