Account Types

Bank
The bank account type denotes a savings or checking account held at a bank. Often interest bearing.
Cash
The cash account type is used to denote a shoe-box or pillowcase stuffed with cash.
Credit
The Credit card account is used to denote credit (e.g. amex) and debit (e.g. visa, mastercard) card accounts.
Asset, Liability
Asset and liability accounts indicate generic, generalized accounts that are none of the above.
Stock, Mutual Fund
Stock and Mutual Fund accounts will typically be shown in registers which show three columns: price, number of shares, and value.
Income, Expense
Income and expense accounts are used to denote income and expenses. Thus, when data in these accounts are displayed, the sign of the entries is reversed from its usual meaning.
Equity
Equity account is used to balance the balance sheet.
Currency
Currency Accounts are used for trading currencies. In many ways, they behave like stocks, except that the computation of the value is different. Note that transfers cannot be made directly between two accounts denominated in different currencies. Such transfers may only be made into currency trading accounts. (Safety checks may be a bit broken still ... )