No visa, 4 months stay: USA

No visa, 3 months stay: Pre-2004 EU (Austria, Belgium, Britain, Denmark, Finland, France, Germany, Greece, Ireland, Italy, Luxembourg, Netherlands, Portugal, Spain, Sweden), Algeria, Andorra, Antigua & Barbuda, Argentina, Bahrain, Barbados, Bermuda, Bosnia & Herzegovina, Brazil, Brunei, Bulgaria, Canada, Chile, Côte d'Ivoire, Dominica, Fiji, Gambia, Guinea, Honduras, Hong Kong, Iceland, Japan, Kiribati, South Korea, Libya, Liechtenstein, Macedonia, Malaysia, Maldives, Mali, Mauritania, Mauritius, Monaco, Morocco, Niger, Norway, Oman, Qatar, Romania, St Kitts & Nevis, St Lucia, Senegal, Serbia & Montenegro, Seychelles, Solomon Islands, Switzerland and Turkey.

No visa if travelling with a tour group: Czech Republic, Hungary, Latvia, Lithuania, Poland and the Slovak Republic.

Visa on arrival, 3 months stay: Australia and South Africa.

Pre-arranged visa. All other countries. Note that New Zealand is within this group.

Extensions may be had, but involves some fuzz. Check with the nearest police station to the place where you stay, and be there at least 2 weeks before your visa expires.