Contiki tours - http://www.contiki.com would have to be my favorite tour group out of them all.
They do just about everything for you, all you need to do is pick what trip you want to go on, and that's a hard task since they offer so many great options.
Contiki has 3 distinct types of tours. Camping, Concept and Time out.
Camping is just that, camping. You pitch tents, you help with the cooking and cleaning up and you sleep in the great outdoors.
Everything about the trip is the same as the others, except for this one difference. It of course is the cheapest option available.
Concept tours are my favorite, you always get a good age range, from 18 to 35 and 80% are singles traveling by themselves. You sleep in cabins and you help with some chores.
Time out tours are the upper class tours that Contiki offers. You stay in hotels, (nothing 5 star) and the people on the tour seem to be a bit older and probably 30 to 50% go with partners.
Contiki also has resorts in Bali, Australia and Greece. I stayed at a Contiki resort in Greece for 5 days and had a blast. It's usually full of people who are taking a break from a tour and just want to sit back and relax for a few days before they get back on a tour.
On Contiki tours you spend a lot of time on a bus with your fellow tour mates so if you get bored easily, bring a good book, Mp3 player or something to keep you amused.
Most people sleep on the bus during the day and party at night.
I've done 6 Contiki tours in the past 5 years. 4 concept tours and 2 time out tours and I had a blast every time.
The most popular tours seem to be....
• European Experience
• European Adventurer
• European Vista
• Simply Italy
• European Whirl
Those are just the trips to Europe. Contiki also goes to America, New Zealand, Australia, UK, and even the Middle East.
Go Contiki is all I can say, you will make friends for life, see the world in an organized fashion with genuinely nice people.
It's funny how so many nice people can be on one tour, and on every tour I go on. Contiki attracts a good crowd and very fun crowd.