I tend to travel with very little and have done it a few ways, one bag inside another to check in and bring two back, bought a bag over there as Diz suggests (which has the benefit of taking only hand luggage with you outbound) and also checked in empty bags, never a problem.
Watches and DVDs have never cuased me a problem either, but customs may well react to such things differently in different places. DVDs are only 150baht or so anyway, I always bring some back.
On the watch front, I know others will have had different experiences but I have never bought a reliable one yet, and at least half have been knacked before I got on the plane home.
