Regular account. Income is taxable as you make it. Capital gains rules apply. You can add money at any time.
IRA. Income is taxable when you withdraw it. Capital gains rules do NOT apply. You can only add up to $5000 a year, provided you have earned income and your income isn't too high.
Normally savings acct is held at a bank and usually only cash is held in acctount (very safe and insured by FDIC, per limits) However you can also have a savings acct with a brokerage firm and you are able to buy stock and mutual funds (the value of your account can fluctuate.
You are able to withdrawal your money at any time.
IRAs are investment vehicles designed for retirement. You can open them at a bank or brokerage firm and normally you have stocks and mutual funds to help grow the money and stay ahead of inflation in order to have a good retirement. The down side is that if you touch the money before you turn 59 1/2 yrs of age there may be a penalty from the IRS
Many people have both accts
Savings for money they may need (vacation, liviing expenses, etc)
IRAs money they do not intend on touching until retirement.