Considering visiting Thailand then consider obtaining a tourist visa for Thailand instead of risking your holiday with a visa on arrival. The visa laws have changed over the last few years as the government attempt to cut down on visa abuse where people lived in Thailand on back-to-back tourist visas. These are the basics for the tourist visa.
If you are married to a Thai and have registered your marriage in Thailand then you can now live in Thailand with your Thai wife or husband if you meet the financial requirements for the marriage visa or Thai "O" visa. These are the basics for the visa and how best to obtain the visa if you already live in Thailand.