Are the addresses in my Wallet client considered to be all as only 1 account or wallet? I'm using the Bitcoin Wallet Client and I've noticed that you could create as many addresses as you want. But I also noticed that there's only 1 Total Amount for the wallet. So does that mean that you could have multiple addresses, but all of that points to same single wallet?

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And so, if my wallet contains several addresses, when I would like to send coins to another address of another person, do I need to create another address to send the coins? Or do I need to send coins one by one from each address? Or could I just send from one address since all of the addresses are in the same wallet?
In the Bitcoin protocol and network there is no concept of "wallet" or "account". It only recognizes addresses. Whoever has the key corresponding to an address can spend the coins in it.

A wallet is merely a collection of addresses with their corresponding keys. The Bitcoin-qt client manages for you a wallet file on your computer. Every address in this wallet is spendable by you, so the software displays the total amount in all addresses as your balance. You don't really need to know how many coins are in each address, you just want to know how much you have in total.

I wouldn't say that the addresses "point" to a wallet as that would imply the wallet is a thing on its own. Note that you can have the same address in several wallets, but that's not recommended.

Some other software, such as Multibit, allow you to easily manage several wallet files, and see the total balance for each.