Pile of credit cards © Image Source, Getty Images

People who carry balances aren't supposed to use reward cards, since plastic that offers cash back, travel points or other goodies tends to come with high interest rates.

New offers may be changing that math, however. Issuers are taking advantage of the current monetary environment to offer attractive low rates with lucrative cash-back offers. At the same time, card companies are pulling back from the hefty sign-up bonuses they offered in previous years that turned some consumers into hobbyists chasing giant piles of points, miles and other incentives.

"For those looking to pay down debts, and particularly to do so while earning rewards, this is an ideal time," said Anisha Sekar, vice president of credit and debit for card-comparison website NerdWallet. "For rewards hackers and bonus seekers, less so."

Among the best low-rate offers, the Discover it card carries a 0% rate for 18 months on balance transfers and for six months on purchases, plus 5% cash back on bonus categories up to $1,500 spent per quarter, Sekar said. Chase Freedom also has 5% bonus categories up to $1,500 spent, she said, and gives 15 months of 0% interest on transfers and purchases.

Industrywide, such 0% offers last an average of only 10 months, according to Card Hub's most recent Credit Card Landscape Report.

The upfront bonuses tend to be meager nowadays. Capital One Venture no longer has the Double Miles challenge, which offered up to 100,000 bonus miles in 2011 and 2012. Southwest reduced its sign-up bonus from 50,000 miles to 25,000, and no-fee cash back cards such as Chase Freedom and Capital One Cash lowered their upfront reward to $100 from $150 or even $200 in earlier years.

Still, there are plenty of good rewards cards that may beat what you have in your wallet. Issuers tend to start out with big bonuses and generous rewards to garner buzz, only to water down their offers over time, said Michael Dolen, founder of CreditCardForum.

Here are some of the cards recommended by Card Hub, CardRatings.com, CreditCards.com, CreditCardForum and NerdWallet.

Travel

The Capital One Venture card once again emerged as an expert favorite, even without a fat sign-up bonus. You earn two miles per dollar spent, and each mile is worth a penny toward any travel purchase, any time. You simply apply your rewards toward any airline, hotel, car or other travel charges made on the card.

"Unlike airline frequent flier miles, with Venture miles you don't have any hoops to jump through," Dolen said. "You're basically earning 2% on your spending." The card has a reasonable annual fee of $59, waived the first year, and no foreign transaction fees.

CardRatings.com's managing editor, Amber Stubbs, recommended two other cards: the Southwest Airlines Rapid Rewards and the Starwood Preferred Guest. The Starwood's value for hotel room redemption is "one of the best," Stubbs said, plus points can be transferred to many frequent flier programs with a 25% bonus. The Southwest card was voted best travel credit card in this year's Freddie Awards. "Southwest goes a long way to keep cardholders happy with perks like free checked bags, anniversary bonus points, no change fees, no foreign transaction fees and flexible redemption options," she said. 

Cash back

Experts were divided about which card offered the best cash-back deals, so pick the one that best fits your spending. Among the nominees:

Chase Sapphire Preferred. Two points per dollar spent on travel, one point on all other purchases, a 7% annual bonus dividend on all points earned on purchases, plus 1-to-1 transfers to leading travel programs. For those itching for sign-up bonuses: Spending $3,000 in the first three months triggers a $500 statement credit valid for travel expenses. There is no annual fee for the first year, "so there's no fixed cost of obtaining this cash bounty," said Odysseas Papadimitriou of CardHub.com.

Blue Cash Preferred from American Express. Get 6% cash back at supermarkets, 3% at gas stations and department stores, and 1% on everything else. "It's therefore a great everyday spending card and would help people taking road trips this summer save a lot in the process," Papadimitriou said. "While this card does charge a $75 annual fee, you also get a $150 initial rewards bonus for spending $1,000 in the first 90 days." If you don't want to pay the annual fee, the Blue Cash Everyday Card is a good choice, with 3% back on groceries, 2% on gas and department stores and 1% on everything else, plus a $100 bonus for spending $1,000 in the first three months, said Bill Hardekopf of LowCards.com.

Image: Liz Weston

Liz Weston

Chase Freedom. The no-fee Freedom gives 5% cash back in rotating bonus categories, up to $1,500 spent quarterly, Sekar said. Amazon.com and select department stores get the extra reward in October through December, "in time for the holiday shopping season," Sekar said. "The card is versatile and earns bonus rewards in everyday categories, and it has the largest sign-up bonus ($100 after spending $500 within three months) of any no-annual-fee, cash-back card."

U.S. Bank Cash+ Visa Signature. This card is less lucrative than it used to be, but its rewards flexibility "is truly groundbreaking," said Curtis Arnold, founder of CardRatings.com. Unlike other cards that offer 5% rebates in rotating categories, this card allows you to choose and change which categories of spending earn extra points. You get 1% back on other spending and a $25 bonus when you redeem $100 or more. "One potential downside is that you have to apply in person at a US Bank branch, and there are a lot of smaller cities that don't have branches," he said.

BankAmericard Cash Rewards. Ben Woolsey, director of marketing and research for CreditCards.com, likes this card for its "strong upfront bonus" and rewards structure – plus you can get a 0% introductory rate for 12 billing cycles on purchases and transfers made in the first 90 days. This no-annual-fee card offers a $100 bonus after you spend $500, with a 3% rebate on gas and 2% on groceries for the first $1,500 in such spending each quarter, plus 1% on everything else.

Click here to become a fan of MSN Money on Facebook

Fidelity Investment Rewards American Express. Unlimited 2% cash back on every purchase and no annual fee. "What's not to love?" Dolen said. "The only catch is that you will need to have a Fidelity account in order to apply."

For all these cards, the usual caveats apply: You typically need excellent credit scores (FICOs of 750 or above) to qualify, and you shouldn't apply for any credit card if you will be in the market for a major loan such as a mortgage or auto loan, since your application can ding your scores.

Liz Weston is the Web's most-read personal-finance writer. She is the author of several books, most recently "The 10 Commandments of Money: Survive and Thrive in the New Economy" (find it on Bing). Weston's award-winning columns appear every Monday and Thursday, exclusively on MSN Money. Join the conversation and send in your financial questions on Liz Weston's Facebook fan page.

More from Liz Weston