I opened an account very recently ( on a 30 day vis extension ) with Bangkok Bank
After visiting several banks ( with Thai girlfriend) and being turned down . .
I visited Thai immigration, who after confirming I was legitimately staying with her at her address . . . Gave me a form ( in Thai ) to take back to the bank, and was able to open the account . . . ( my experience recently in Prachinburi) the bank clerk spoke only a little English and the guy at immigration spoke English fluently and was really helpful .
.
If you visit immigration and the bank,
take photocopies ( several ) of everything . .
Passport including page with your Visa, girlfriends ID, proof of her address etc . . Good luck . . .
Yes, it definitely worth going to Langkawi, some beautiful beaches and chilled spots there ..... several ferries a day to and fro Kih Lipe and Langkawi . . . Enjoy ....