This is the point:

I am just a step from buying a KingMax 1 GB MMC but I am still wondering if it will work all fine.

Anyone tried a 1 GB MMC in Nokia 3650?
Does it slow down?
Work at all?
Allow MP3 playback? (some people using MMCs below 512 were having issues on playing MP3... weird!?)
Anything against this maker - KingMax?

Some may ask, why soooo much space??
I answer - well, if u can buy a 256 MMC for 40$ or a 1GB MMC for 65$? What would u do???

I need help!!

i have nokia 3650 and 256mmc it works fine and plays mp3´s perfectly.But in store they said that 256mb is max no 512 or 1gb will work on it.If you are planning to use the phone as mp-3 player,my opinion its not worth it rather buy ngage or nokia 3300 they both have stereo but nokia 3650 has mono output.The sound quality is pretty crappy.

according to what they say it is compatible with 3650

http://www.mobymemory.com/1Gb_MMC_Memory_Card_for_Mobile_phones.asp

be warned, the greater the size of the MMC the slower the processing of the phone!