(CNN) -- Vacationers will follow the sun and the deals this summer, travel service companies say.
The economy still appears to be weighing on travelers' decision-making. In a Travelzoo survey, 74 percent of respondents said they will take a vacation this year only if they find a bargain.
"An overwhelming majority of people will need a deal to travel in 2010," said Gabe Saglie, senior editor at Travelzoo.
Cruise lines have been offering "eye-popping" deals since last year, Saglie said.
"Stiff competition is prompting cruise lines to sweeten deals with onboard credits and kids-free promotions," he said.
Destinations in Mexico are countering bad press with good values, and "the U.S. dollar goes a long way in Belize, Costa Rica, Guatemala, Honduras and Panama," Saglie said.
China hasn't seen the tourism boom it expected after the 2008 Summer Olympics, so hotels there are slashing rates to attract business, he said.
Familiar names dominate the top summer destinations for online travel booking sites Orbitz and Travelocity.
Las Vegas, Nevada, is a perennial winner. The gaming and entertainment mecca is No. 1 on Orbitz's list and and No. 2 at Travelocity.
Orlando, Florida, home to a bevy of family-friendly theme parks, ranks at the top of Travelocity's list and No. 4 at Orbitz.
Deals are available in resort-heavy Cancun, Mexico, which ranks second at Orbitz and No. 7 at Travelocity.
"A lot of the top 10 looks similar to what we saw same time last year," said Jeanenne Tornatore, spokeswoman for Orbitz. "Orlando and Maui [Hawaii] have moved up in popularity as compared to last year.
"In the top 25, there are some interesting things going on," she added. Cozumel, Mexico; Paris, France; and Venice, Italy, all moved into the top 25 after being unranked last year, she said.
"Overall, average daily hotel rates are very similar to last year," but there are exceptions, Tornatore said. "[Mexico's] Riviera Maya, which is No. 3 in the top 10, is seeing some better deals than last year. Average daily rates are down over 12 percent."
Travelzoo's researchers put together a list of where they think the best deals are likely to be found this summer. Travelzoo's Top 5 deal destinations for 2010 are the Caribbean by cruise, Central America, China, Las Vegas and South Africa, home of soccer's FIFA World Cup tournament June 11-July 11.
Don't expect great deals in South Africa during the World Cup, Saglie warned, but good deals are available on airfare and safari trips before and after the tournament.
International travel giant Carlson Wagonlit's CWT Vacations division compiles information on the types of vacations people are booking rather than specific destinations.
"Cruises are the most frequently booked summer travel option by our clients," said Gerard Bellino, Carlson Wagonlit's vice president of U.S. leisure.
"Alaskan cruises are most popular for summer travel, followed by Mediterranean and European cruises. Hawaii, Italy and Europe in general continue to be top choices for travelers who are not cruising this summer."