Here are two ideas for startups that I'd like to use myself. Please make them a reality or convince someone to create them (help by sharing this on your profile).

1. GOAL-ORIENTED TRAVEL SEARCH

The user picks activities (spa, tanning, skiing, partying, ...), weather (cold, neutral, warm, hot), status (single, couple, family) and/or age and gets a list of hotels in selected world destinations that fulfill his needs. If the user defines his location, he also gets a list of possible transportation options (flight, train, bus, ...). Everything gets combined and shows up sorted by price. Integrate it with Facebook to let the user find friends who might want to join him on such a trip ("John Wayne wants to go skiing. Do you want to join him? Take a look at available options where you can go together."). Include offers from Airbnb.

This is for people who care more about what they'll be doing on their holiday instead of where they'll be going. They want to get a quick overview of available options throughout the world.

2. LUXURY TRAVEL SEARCH

The user picks a destination and optionally his location. He gets an overview of the most expensive available rooms in the most luxurious hotels at this destination. If he picked his location, he will also get an overview of possible transportation options (first class/business class flights, chauffeur service, ...). Everything might be sorted by price. Include offers from Airbnb.

This is for people who care more about their travel comfort than the travel cost and are tired of clicking through all the clutter on regular travel search sites. They already know where they want to go, but don't know where to stay.