That may seem a silly question since most people would answer : “In the local shopping mall”. But, if you’re reading this, you would probably give a different reply. Here’s our U.S. finance correspondent to give his answer :

What should you do with your idle cash? Let’s say you’re responsible and you’ve accumulated an emergency fund. This is money that you can’t take risk with, but it would be nice to earn something on it, right? Depending on what you want, the world is full of options.

You can always leave it in a checking or savings account. Of course, you won’t earn much. Most brick and mortar banks are still paying almost nothing on deposits. However, the internet bank accounts make it more appealing. HSBC, INGDirect, and Capital One all have competitive rates these days – with no fees or minimum balance requirements. Whatever bank you use, make sure it’s FDIC insured.

You can also use money market funds. These are technically mutual funds that invest in short term issues. The advantage of a money market fund over a bank product is that the interest rate will likely change more rapidly (of course, that’s only an advantage if rates are going up and not down). The disadvantage of a money market is that there’s technically a possibility that you can lose your money if the underlying “money markets” fall apart. Read the fund’s prospectus to see what it invests in, and how you feel about that risk.

With a money market, you can sometimes get a checkbook to access your cash. They don’t like for you to write small checks, so they impose a minimum check size (like $500 per check). With a bank product, you usually link your account to a checking account and move money electronically when you’re ready to spend it. With either type of account, you can make deposits by check or electronically.

Which is better? It depends. Look them both over, compare rates, and figure out what suits your needs.

Scott Adams, who wrote the Dilbert books in the U.S., once concocted a 9-point plan for sorting out your money, which he called, The Unified Theory of Everything Financial.

Here it is adapted for the UK market :

1. Make sure you have a will.

2. Pay off all your credit cards.

3. If you have a family to support, get term life insurance.

4. Ensure you fund your company pension to the maximum.

5. Buy a house.

6. Put £3000 in a tax-free Isa savings account each year. (£3000 is the current maximum).

7. Any money left over, invest 70 percent in a stock index tracking fund, and 30 percent in a bond fund through any discount broker/fund supermarket. Don’t touch it until retirement.

8. For special cases, or lack of expertise, hire a fee-based financial planner, not one who charges a percentage of your portfolio.

Good advice, so pass it on to anyone you think may need it.

It’s emerging that the British tax authority Revenue & Customs believes tens of thousands of buy-to-let landlords are error-prone in their tax returns. So much so that reports have suggested a crackdown by the Revenue.

However, a spokesman responds, “The idea that we’re dragging in hordes of buy-to-let investors to face some medieval inquisition is just so wide of the mark.” They are, he said, worried that many people are confused about the tax regime, and up to 80,000 may be paying the wrong amount.

Letting property carries a much more complex tax calculation than the normal buying and selling of houses. In many cases it may be that investors are not claiming all their allowances and therefore overpaying.

There is a long list of expenses that can be claimed against rental income. The most obvious one is interest on any mortgages used to buy the property. Capital repayments, however, are not covered by this.

Landlords can also claim 10 percent of annual rental for “wear and tear”, effectively depreciation of furnishings, fittings and the fabric of the house. Insurance is also deductible, as are fees paid to managing agents. Legal and accounting fees are included too.

If you sell the property you must pay 40 percent capital gains on the profit, unlike your main residence which is exempt. However, the first £9,200 of profits in any year are free from tax.

If you have owned the property for more than three years, you can save 40 percent on CGT, and there’s further relief if you have lived in the property. One ploy used by canny landlords is to let their own house for six months, while living themselves in a rental property due for sale, thus eliminating CGT altogether.

As with any relationship with the Revenue, it pays to be on top of the detail.

The UK population now has debts of £1.3trillion ($2.5tn) — more than £28,000 ($55,000) for every adult in the country.

In a new survey, most of Britons say they would need at least £100,000 ($200,000) to make a real difference to their lifestyle. They would use it simply to get their finances back on track.

In the survey, of more than 2,000 savers and spenders by National Savings and Investments, more than 60 percent estimated £100,000 as the very least they would need to improve their lifestyle.

At the other end of the scale, only 6 percent would be satisfied with a £1,000 ($2000) windfall. Commentators say a culture of “keeping up with the Joneses” is to blame, with many of people “going large” on holidays and expensive restaurants.

Higher earners too are not content. One in ten said a windfall of £2million ($4m) would be needed before they would really notice the difference.

John Prout, sales director at NS&I, said the figures reflected a change in national spending habits with more of us treating ourselves to everyday luxuries.

‘When Premium Bonds were launched in 1957, £1,000 was a life-changing amount and for many it meant security and a comfortable future. But foreign holidays and eating out, which used to be considered a luxury, are now a part of normal life. It is not surprising that the amount needed to have the same effect has shot up over the last 50 years.

“However, for a significant number, a windfall is now less about looking forward and more about a way to get back on track financially, and pay off past indulgences.”