Cambodia forum

If you only have a week, I think I would suggest Cambodia. A week is enough to see the highlights of Siem Reap (maybe 4 days) and Phnom Penh (3 day). You can fly into PP, then easily bus to Siem Reap (6 hour, a pleasant bus ride for $7 or so, with a 1/2 hour stop along the way). From Siem Reap you could head overland back to Bangkok (if you need to fly out of there) and maybe stop at the NE Islands (Koh Chang, etc) on the way back through.

Alternatively, you could also spend a week, say in Northern Thailand (Vientiane, Vang Vieng and Luang Prabang would be the standard route) - but expect to spend more time on buses, etc. Of course, it depends on where you will be in Thailand as to which option makes logistical sense. And it depends on your interests, of course.

You could add some adventure to the Cambodia leg of the trip by taking 2 days and going up to the Preah Vihear temple on the Thai border. The tensions have supposedly died down and there's apparently very few tourists up there now. Might have the whole place to yourselves.

One week? I would say Cambodia, but either country would involve some flying, I would think. BKK to Phnom Penh, bus to Siem Reap, then fly back to BKK. Or, BKK to Vientiene, bus to Vang Vieng, bus to Luang Prabang, then back to BKK via air. The latter would be more rushed, I would think.

Or, in Thailand you could go to Issan, for example, or up to Nan. But if you want to see Angkor Wat and surrounds, well, there really is nothing like it elsewhere (which is why you will encounter so many other touristic types there).