Pros and cons of using Mt. Gox as an e-wallet Mt. Gox obviously allows you to send bitcoins to it, and to receive them to an address of your choice; hence I'm wondering if there is any reason not to use it as an e-wallet.

Unless I'm mistaken, it's much bigger (by far) than any other bitcoin exchange, bank or proper e-wallet, so we can reasonably expect it being more secure, supported and safe.

Why should I use a specialised e-wallet instead?
Because Mt.Gox has to abide by anti money laundering laws they require at least some form of identification. Although this is a requirement for Fiat to Bitcoin conversion there is no need to link your normal bitcoin transactions to your Bank Account / Identity. Wallet services that deal solely with bitcoin do not need to comply with AML laws and hence require no identification or bank details.
Mt.gox doesn't support many features that My Wallet does: Export private keys - Generate New Address - Unconfirmed transactions - Alerts - Multi Recipient Transactions - Paper Wallets - Labelling Addresses.
Even though Mt.gox is the largest and most trusted exchange you are still using them as a bank and are not in control of your own private keys. One of the key advantages of bitcoin is it allows you to be in control of your money without needing a third party. With the new javascript based wallet services your keys are encrypted and decrypted inside your own browser so you never share your keys with the server. Some trust is still required unless you use a paper wallet, but it is at least a happy medium.
Withdrawal limits.
No way to know if Mt.Gox actually has your funds and is not operating as a fractional reserve.


Disclaimer: I am biased because I operate My Wallet