Worst
3.)
Nha Trang Airport (NHA) The old US airbase, not the new airport. No A/C in the jungle, and the terminal really hasn't seen much repair since the Americans left it. Reminds you of a Chuck Norris MIA movie set. Was there 4 years ago on a charter.
2) Victoria Falls,
Zimbabwe. Sadly I actually think this is the best airport in all of Zim right now... given it is 99% tourists. After you land you're in a cattle hall waiting to pay Mugabe's henchman his $75 cash only single entry visa. No conveyor belt luggage, it's all hand dropped so you have 200 people wandering around bags trying to find theirs. Way too small to handle 2 737's so you're packed in there in the non A/C heat. 1 barely there "lounge" available for feeble soft drinks. Oddly the pre security areas were not nearly as offensive, other than the tortoise slow gate people (a common theme in Africa)
1) Worst of all time.
Nairobi. What a craphole considering it is East Africa's main airport. And this was the nice side - the "international terminal". Only had crappy benches for about 25 people, and 1 lousy coffee shop. About 6 places to buy smokes and booze though. Dirty, hot, and jsut crappy all over. Agents have cardboard signs they stealthily put up over the gate with no annoucements. Hope you like lines, as you can spend hours if you want get to the Kenyan Airways counter for help. Place was tiny too - About the size of the main floor at the Bay in Downtown Calgary except in a 25 foot wide strip. It's a circular building like the old Toronto T1. It's a major hub into Kigali but the Mountain Gorillas in Rwanda were worth it though. Oh and they lost my backpack here right before I went on a 15 day safari....I was luck to get it back as lost luggage here tends to stay lost....
Here's some pics:

yes it's that's narrow. Notice the lack of seats...anywhere. That plasma is bogus, none were working when we were there 2 years ago.

Seats are these weird roll around on your own deals. Usually all pushed into a corner. Note the everpresent unfinished construction:
Best
1) Hong Kong. In town check-in and a high speed train were absolutely amazing. It would be like checking your bags in at Bankers Hall downtown at a counter. Boarding a bullet train to the airport, clearing security and sitting in a chair by the gate in 23 minutes. Speedy, efficient, and clean. What more do you want?
2) Schiphol - Kind of dated, but having the metro, overland train, and airport all on top of each other are absolutely amazing. Contrast that with Heathrow and getting to St Pancras from Heathrow on the Tube....
3) St Pancras Eurostar. OK it's a train but what an amazing restoration of a Victorian era building. Taking the train is loads more civilized than flying. Relaxed and comfy preboard area. Good shops and eateries. Annoying lack of garbage cans - thank you IRA.