Hi...
Lock and Key - You can buy ones in Goa, save having to carry it... Any Hardware shop will sell them...
Teabags / Coffee - If you like a particular brand then OK, although Nescafe and Tetley are avilable here....
Thermal Mugs - Also available here...
Mp3 player & Speakers - Yes, wouldn't go anywhere without music! :o)
bandages, iodine - Good idea, but only useful if you're going to carry them with you everywhere, these are avilable in all chemists, although bandages are always as good over here...
painkillers - buy here, more than likely cheaper!
tablets for reducing any unwanted stomach and bowel activity - again you can probably buy here cheaper
Agree with KJF - Cheese, Jam, dilute pop, bacon, sausages are probably good things to bring if you might miss them in two weeks (if not for yourself then for me! :o)
Also agree with Candybabe - A positive calm mind to deal with the beggers etc, just chill', it's a much easier way to put up with the hassle - ask where they are from, it's nice to talk... Sense of adventure - don't stick by the pool, go out and explore - try the buses - don't live in a taxi, walk don't just stay on one beach..
Also passport and visa might be handy!