The correct rate for present value calculations is the discount rate.
The inflation rate is inferior because it does not allow for other considerations such as risk.
A quoted "interest rate" is context dependent so it cannot be evaluated by the magnitude of the rate alone. Which person or organization is quoting the rate? Is it wise to rely upon the quote? If it is a person, is this person willing and able to repay a loan? Is it a bank? Are deposits at that bank protected by an insurance plan? Does a government control the insurance company? Has the government created the conditions for reliable deposit insurance?
The most appropriate discount rate is not a quote from another person or organization. The discount rate must be particular to the contemplated investment and your circumstances. One way to arrive at a discount rate is to consider the following...
discount rate =
expected inflation rate +
expected real growth rate of the economy +
uncertainty factor +
expected real growth rate of the economy =
expected nominal growth rate of the economy -
expected inflation rate
The uncertainty factor is also called the risk premium. Since the expected inflation rate is added in one equation but subtracted in the other equation, a simplification is possible.
If you are contemplating a bank deposit you might wonder why it is necessary to consider the growth of the economy. If you control your investments, you might consider investing in a business. Attractive alternatives increase your required return for a bank deposit. If this alternative is unlikely or impossible, then economic growth is a less important factor, however, it never disappears completely because the bank's health is economically dependent.