As of Feb 1, the new 700 Baht tax (raised from 500 Baht) will be included in the final ticket price for international departures, just like the domestic departure tax has long been included.

There's lots to do on Sukhumvit.

It's one of Bangkok's main commercial arteries and contains its biggest tourist mile (from Nana to Asoke). There are literally hundreds of hotels, restaurants, clubs, dives, bars, fast food chains, shopping malls and just about anything else you could imagine (and I mean ANYTHING you could imagine) on the main Sukhumvit Road or its side streets and lanes (sois). One of the major sois (a main street in its own right), Thonglor, has become an up-and-coming venue for arty young Thais and is worth checking out for its cafés and wide range of restaurants alone.

The Nana-Asoke strip has a lively street market in the early evening and a different sort of action after about 10 PM. After the bars close at 2 AM (or 1 AM or whatever it is now), Sukhumvit becomes a big informal beer bar with food and drink vendors materializing out of nowhere and all the bar workers, bar patrons, streetwalkers, freelancers, ladyboys, tourists, ex-pats, and other denizens of the night drinking and eating until the wee hours.

And last but certainly not least, the BTS/Skytrain runs the length of the urban part of Sukhumvit (the street continues out of Bangkok to Pattaya and beyond). So from Sukhumvit you can easily and quickly go up to Chatuchak market, for instance, or down to the river to catch the Chao Phraya Express boats which take you up to tourist sights like the Grand Palace and Wat Arun. The Chao Phraya boats are one of the greatest cheap excursions in Bangkok. You can start at Saphan Taksin/Sathorn (where the Skytrain ends) and take the boats all the way up to Nonthaburi, which is another province, jumping on and off the boats, for a couple of dollars. In Nonthaburi you can have lunch at the floating restaurant a few hundred metres downriver and watch the traffic on the river, before catching a boat back.

Don't feel you need to take organized tours to explore Bangkok. It's an easy city to get around. Taxis are cheap and plentiful (just don't take the ones lurking around hotels and tourist sights, and make sure they use their metres). Many people speak English. But the ones who try to tell you that the Grand Palace (or any other tourist sight) is closed are scammers and should be ignored. (Or you can fend them off with some Thai: "Mai ao khrap/ka!" Pronounced: "Mye ow c'ap" (for a man) or "Mye ow kaaa" (for a woman).

The only time when you really should take a tour is to those places where you need an explanation of the cultural context of something like the Grand Palace or the Emerald Buddha.

The tours themselves are something of a scam. Bangkok tour guides have to pay the tour companies to be allowed to work, and the only way they have of recouping their investment and making a living is to take their charges to restaurants, souvenir shops and gem factories which pay commissions. Even so, those commissions are split between the guide, the tour company and the driver.